diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ea65cf7..f50896d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,7 +9,7 @@ jobs:
     strategy:
       matrix:
         php: [ 8.3, 8.2, 8.1 ]
-        database: [ mysql, mariadb, pgsql, sqlite, sqlsrv, singlestore ]
+        database: [ mysql, mariadb, pgsql, sqlite, sqlsrv, singlestore, firebird ]
         release: [ stable, lowest ]
         include:
           - php: 8.3
diff --git a/README.md b/README.md
index b2a7377..08d6e9b 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,7 @@ This Laravel Eloquent extension provides recursive relationships for [trees](#tr
 - SQLite 3.8.3+
 - SQL Server 2008+
 - SingleStore 8.1+ (only [trees](#trees-one-parent-per-node-one-to-many))
+- Firebird
 
 ## Installation
 
diff --git a/composer.json b/composer.json
index 382ea96..0b3b47c 100644
--- a/composer.json
+++ b/composer.json
@@ -12,11 +12,12 @@
         "php": "^8.1",
         "illuminate/database": "^10.0",
         "staudenmeir/eloquent-has-many-deep-contracts": "^1.1",
-        "staudenmeir/laravel-cte": "^1.8"
+        "staudenmeir/laravel-cte": "^1.10"
     },
     "require-dev": {
         "barryvdh/laravel-ide-helper": "^2.13",
         "doctrine/dbal": "^3.5.2",
+        "harrygulliford/laravel-firebird": "^3.2",
         "larastan/larastan": "^2.0",
         "mockery/mockery": "^1.5.1",
         "orchestra/testbench": "^8.15",
diff --git a/docker-compose.yml b/docker-compose.yml
index 4152167..b498c2e 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -75,6 +75,14 @@ services:
       - test
     volumes:
       - .docker/singlestore/init.sql:/init.sql
+  firebird:
+    image: jacobalberty/firebird:latest
+    environment:
+      FIREBIRD_DATABASE: 'test.fdb'
+      ISC_PASSWORD: 'password'
+      EnableLegacyClientAuth: 'true'
+    networks:
+      - test
 
 networks:
   test:
diff --git a/src/Eloquent/Relations/Traits/IsOfDescendantsRelation.php b/src/Eloquent/Relations/Traits/IsOfDescendantsRelation.php
index cf7c681..e0b999c 100644
--- a/src/Eloquent/Relations/Traits/IsOfDescendantsRelation.php
+++ b/src/Eloquent/Relations/Traits/IsOfDescendantsRelation.php
@@ -276,8 +276,11 @@ protected function getInitialQuery(ExpressionGrammar $grammar, callable $constra
 
         $depth = $grammar->wrap($model->getDepthName());
 
-        $query = $model->newModelQuery()
-            ->select('*')
+        $query = $model->newModelQuery();
+
+        $table = $alias ?: $query->getQuery()->from;
+
+        $query->select("$table.*")
             ->selectRaw("$initialDepth as $depth");
 
         if ($alias) {
diff --git a/src/Eloquent/Traits/BuildsAdjacencyListQueries.php b/src/Eloquent/Traits/BuildsAdjacencyListQueries.php
index 209ba04..db7fcc4 100644
--- a/src/Eloquent/Traits/BuildsAdjacencyListQueries.php
+++ b/src/Eloquent/Traits/BuildsAdjacencyListQueries.php
@@ -5,6 +5,7 @@
 use Illuminate\Database\PostgresConnection;
 use PDO;
 use RuntimeException;
+use Staudenmeir\LaravelAdjacencyList\Query\Grammars\FirebirdGrammar;
 use Staudenmeir\LaravelAdjacencyList\Query\Grammars\MariaDbGrammar;
 use Staudenmeir\LaravelAdjacencyList\Query\Grammars\MySqlGrammar;
 use Staudenmeir\LaravelAdjacencyList\Query\Grammars\PostgresGrammar;
@@ -104,6 +105,10 @@ public function getExpressionGrammar()
                 return $this->query->getConnection()->withTablePrefix(
                     new SingleStoreGrammar($this->model)
                 );
+            case 'firebird':
+                return $this->query->getConnection()->withTablePrefix(
+                    new FirebirdGrammar($this->model)
+                );
         }
 
         throw new RuntimeException('This database is not supported.'); // @codeCoverageIgnore
diff --git a/src/Eloquent/Traits/HasRecursiveRelationshipScopes.php b/src/Eloquent/Traits/HasRecursiveRelationshipScopes.php
index ba492de..4571548 100644
--- a/src/Eloquent/Traits/HasRecursiveRelationshipScopes.php
+++ b/src/Eloquent/Traits/HasRecursiveRelationshipScopes.php
@@ -184,6 +184,8 @@ public function scopeWithRelationshipExpression(Builder $query, $direction, call
      */
     protected function getInitialQuery(ExpressionGrammar $grammar, callable $constraint, $initialDepth, $from)
     {
+        $table = explode(' as ', $from)[1] ?? $from;
+
         $depth = $grammar->wrap($this->getDepthName());
 
         $initialPath = $grammar->compileInitialPath(
@@ -192,7 +194,7 @@ protected function getInitialQuery(ExpressionGrammar $grammar, callable $constra
         );
 
         $query = $this->newModelQuery()
-            ->select('*')
+            ->select("$table.*")
             ->selectRaw($initialDepth.' as '.$depth)
             ->selectRaw($initialPath)
             ->from($from);
@@ -241,7 +243,10 @@ protected function getRecursiveQuery(ExpressionGrammar $grammar, $direction, $fr
         ];
 
         if ($direction === 'both') {
-            $recursiveDepth = "$depth + (case when {$joinColumns['desc'][1]}={$joinColumns['desc'][0]} then 1 else -1 end)";
+            $left = $grammar->wrap($joinColumns['desc'][1]);
+            $right = $grammar->wrap($joinColumns['desc'][0]);
+
+            $recursiveDepth = "$depth + (case when $left=$right then 1 else -1 end)";
         } else {
             $recursiveDepth = $depth.' '.($direction === 'asc' ? '-' : '+').' 1';
         }
diff --git a/src/Query/Grammars/FirebirdGrammar.php b/src/Query/Grammars/FirebirdGrammar.php
new file mode 100644
index 0000000..6a358dc
--- /dev/null
+++ b/src/Query/Grammars/FirebirdGrammar.php
@@ -0,0 +1,75 @@
+<?php
+
+namespace Staudenmeir\LaravelAdjacencyList\Query\Grammars;
+
+use HarryGulliford\Firebird\Query\Grammars\FirebirdGrammar as Base;
+use Illuminate\Database\Query\Builder;
+
+class FirebirdGrammar extends Base implements ExpressionGrammar
+{
+    use OrdersByPath;
+
+    public function compileInitialPath($column, $alias)
+    {
+        return 'cast(' . $this->wrap($column) . ' as varchar(8191)) as ' . $this->wrap($alias);
+    }
+
+    public function compileRecursivePath($column, $alias, bool $reverse = false)
+    {
+        $wrappedColumn = $this->wrap($column);
+        $wrappedAlias = $this->wrap($alias);
+        $placeholder = 'cast(? as varchar(8191))';
+
+        return $reverse ? "($wrappedColumn || $placeholder || $wrappedAlias)" : "($wrappedAlias || $placeholder || $wrappedColumn)";
+    }
+
+    public function getRecursivePathBindings($separator)
+    {
+        return [$separator];
+    }
+
+    public function selectPathList(Builder $query, $expression, $column, $pathSeparator, $listSeparator)
+    {
+        return $query->selectRaw(
+            'list(' . $this->wrap($column) . ", '$listSeparator')"
+        )->from($expression);
+    }
+
+    public function compilePivotColumnNullValue(string $type, int $precision, int $scale): string
+    {
+        return 'null';
+    }
+
+    public function compileCycleDetection(string $localKey, string $path): string
+    {
+        $localKey = $this->wrap($localKey);
+        $path = $this->wrap($path);
+
+        return "position($localKey || ?, $path) > 0 or position(? || $localKey || ?, $path) > 0";
+    }
+
+    public function getCycleDetectionBindings(string $pathSeparator): array
+    {
+        return [$pathSeparator, $pathSeparator, $pathSeparator];
+    }
+
+    public function compileCycleDetectionInitialSelect(string $column): string
+    {
+        return 'false as ' . $this->wrap($column);
+    }
+
+    public function compileCycleDetectionRecursiveSelect(string $sql, string $column): string
+    {
+        return $sql;
+    }
+
+    public function compileCycleDetectionStopConstraint(string $column): string
+    {
+        return 'not ' . $this->wrap($column);
+    }
+
+    public function supportsUnionInRecursiveExpression(): bool
+    {
+        return false;
+    }
+}
diff --git a/tests/Graph/AncestorsTest.php b/tests/Graph/AncestorsTest.php
index 5bf918a..cc49eb9 100644
--- a/tests/Graph/AncestorsTest.php
+++ b/tests/Graph/AncestorsTest.php
@@ -12,7 +12,7 @@ class AncestorsTest extends TestCase
 {
     public function testLazyLoading()
     {
-        $ancestors = Node::find(5)->ancestors;
+        $ancestors = Node::find(5)->ancestors()->orderByDesc('depth')->orderBy('id')->get();
 
         $this->assertEquals([1, 2, 10, 1, 9], $ancestors->pluck('id')->all());
         $this->assertEquals([-1, -1, -1, -2, -2], $ancestors->pluck('depth')->all());
@@ -71,7 +71,7 @@ public function testLazyLoadingWithCycleDetectionAndStart(string $class, array $
 
     public function testLazyLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -113,7 +113,7 @@ public function testLazyLoadingAndSelf()
 
     public function testLazyLoadingAndSelfWithCycleDetection()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -127,7 +127,7 @@ public function testLazyLoadingAndSelfWithCycleDetection()
 
     public function testLazyLoadingAndSelfWithCycleDetectionAndStart()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -171,6 +171,11 @@ public function testEagerLoadingWithCycleDetection(string $class, array $exclusi
             $this->markTestSkipped();
         }
 
+        // TODO[L11]
+        if ($this->connection === 'firebird' && version_compare(phpversion(), '8.2', '<')) {
+            $this->markTestSkipped();
+        }
+
         $this->seedCycle();
 
         $nodes = $class::with([
@@ -188,6 +193,11 @@ public function testEagerLoadingWithCycleDetectionAndStart(string $class, array
             $this->markTestSkipped();
         }
 
+        // TODO[L11]
+        if ($this->connection === 'firebird' && version_compare(phpversion(), '8.2', '<')) {
+            $this->markTestSkipped();
+        }
+
         $this->seedCycle();
 
         $nodes = $class::with([
@@ -201,7 +211,7 @@ public function testEagerLoadingWithCycleDetectionAndStart(string $class, array
 
     public function testEagerLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -240,7 +250,7 @@ public function testEagerLoadingAndSelf()
 
     public function testEagerLoadingAndSelfWithCycleDetection()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -254,7 +264,7 @@ public function testEagerLoadingAndSelfWithCycleDetection()
 
     public function testEagerLoadingAndSelfWithCycleDetectionAndStart()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -293,7 +303,7 @@ public function testLazyEagerLoading()
 
     public function testLazyEagerLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -332,7 +342,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -343,7 +353,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -365,7 +375,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testExistenceQueryForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -387,7 +397,7 @@ public function testWithSumForSelfRelation()
 
     public function testWithSumForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -398,7 +408,7 @@ public function testWithSumForSelfRelationAndSelf()
 
     public function testDelete()
     {
-        if ($this->connection === 'mariadb') {
+        if (in_array($this->connection, ['mariadb', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Graph/CollectionTest.php b/tests/Graph/CollectionTest.php
index 5087007..da67ae0 100644
--- a/tests/Graph/CollectionTest.php
+++ b/tests/Graph/CollectionTest.php
@@ -11,7 +11,7 @@ class CollectionTest extends TestCase
 {
     public function testToTree()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -41,7 +41,7 @@ public function testToTreeWithRelationship()
 
     public function testToTreeWithCycle()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -61,7 +61,7 @@ public function testToTreeWithCycle()
 
     public function testToTreeWithCycleAndStart()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -81,7 +81,7 @@ public function testToTreeWithCycleAndStart()
 
     public function testToTreeWithEmptyCollection()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Graph/Concatenation/AncestorsTest.php b/tests/Graph/Concatenation/AncestorsTest.php
index d32ee3f..131a6e4 100644
--- a/tests/Graph/Concatenation/AncestorsTest.php
+++ b/tests/Graph/Concatenation/AncestorsTest.php
@@ -18,7 +18,7 @@ public function testLazyLoading()
 
     public function testLazyLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -40,7 +40,7 @@ public function testEagerLoading()
 
     public function testEagerLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -76,7 +76,7 @@ public function testLazyEagerLoading()
 
     public function testLazyEagerLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -91,7 +91,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -102,7 +102,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -113,7 +113,7 @@ public function testExistenceQueryAndSelf()
 
     public function testExistenceQueryForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -124,7 +124,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testExistenceQueryForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Graph/Concatenation/DescendantsTest.php b/tests/Graph/Concatenation/DescendantsTest.php
index 04a83ad..470453b 100644
--- a/tests/Graph/Concatenation/DescendantsTest.php
+++ b/tests/Graph/Concatenation/DescendantsTest.php
@@ -18,7 +18,7 @@ public function testLazyLoading()
 
     public function testLazyLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -39,7 +39,7 @@ public function testEagerLoading()
 
     public function testEagerLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -73,7 +73,7 @@ public function testLazyEagerLoading()
 
     public function testLazyEagerLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -87,7 +87,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -98,7 +98,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -109,7 +109,7 @@ public function testExistenceQueryAndSelf()
 
     public function testExistenceQueryForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -120,7 +120,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testExistenceQueryForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Graph/DescendantsTest.php b/tests/Graph/DescendantsTest.php
index 5548fe0..57657cc 100644
--- a/tests/Graph/DescendantsTest.php
+++ b/tests/Graph/DescendantsTest.php
@@ -12,7 +12,7 @@ class DescendantsTest extends TestCase
 {
     public function testLazyLoading()
     {
-        $descendants = Node::find(2)->descendants;
+        $descendants = Node::find(2)->descendants()->orderBy('depth')->get();
 
         $this->assertEquals([5, 7, 8, 8], $descendants->pluck('id')->all());
         $this->assertEquals([1, 2, 2, 3], $descendants->pluck('depth')->all());
@@ -71,7 +71,7 @@ public function testLazyLoadingWithCycleDetectionAndStart(string $class, array $
 
     public function testLazyLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -113,7 +113,7 @@ public function testLazyLoadingAndSelf()
 
     public function testLazyLoadingAndSelfWithCycleDetection()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -127,7 +127,7 @@ public function testLazyLoadingAndSelfWithCycleDetection()
 
     public function testLazyLoadingAndSelfWithCycleDetectionAndStart()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -179,6 +179,11 @@ public function testEagerLoadingWithCycleDetection(string $class, array $exclusi
             $this->markTestSkipped();
         }
 
+        // TODO[L11]
+        if ($this->connection === 'firebird' && version_compare(phpversion(), '8.2', '<')) {
+            $this->markTestSkipped();
+        }
+
         $this->seedCycle();
 
         $nodes = $class::with([
@@ -196,6 +201,11 @@ public function testEagerLoadingWithCycleDetectionAndStart(string $class, array
             $this->markTestSkipped();
         }
 
+        // TODO[L11]
+        if ($this->connection === 'firebird' && version_compare(phpversion(), '8.2', '<')) {
+            $this->markTestSkipped();
+        }
+
         $this->seedCycle();
 
         $nodes = $class::with([
@@ -209,7 +219,7 @@ public function testEagerLoadingWithCycleDetectionAndStart(string $class, array
 
     public function testEagerLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -256,7 +266,7 @@ public function testEagerLoadingAndSelf()
 
     public function testEagerLoadingAndSelfWithCycleDetection()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -270,7 +280,7 @@ public function testEagerLoadingAndSelfWithCycleDetection()
 
     public function testEagerLoadingAndSelfWithCycleDetectionAndStart()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -317,7 +327,7 @@ public function testLazyEagerLoading()
 
     public function testLazyEagerLoadingAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -364,7 +374,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -375,7 +385,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryWithCycleDetection()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -388,7 +398,7 @@ public function testExistenceQueryWithCycleDetection()
 
     public function testExistenceQueryWithCycleDetectionAndStart()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -401,7 +411,7 @@ public function testExistenceQueryWithCycleDetectionAndStart()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -412,7 +422,7 @@ public function testExistenceQueryAndSelf()
 
     public function testExistenceQueryAndSelfWithCycleDetection()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -425,7 +435,7 @@ public function testExistenceQueryAndSelfWithCycleDetection()
 
     public function testExistenceQueryAndSelfWithCycleDetectionAndStart()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -449,7 +459,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testExistenceQueryForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -471,7 +481,7 @@ public function testWithSumForSelfRelation()
 
     public function testWithSumForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -482,7 +492,7 @@ public function testWithSumForSelfRelationAndSelf()
 
     public function testDelete()
     {
-        if ($this->connection === 'mariadb') {
+        if (in_array($this->connection, ['mariadb', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Graph/EloquentTest.php b/tests/Graph/EloquentTest.php
index 3765dc2..2fc1bb8 100644
--- a/tests/Graph/EloquentTest.php
+++ b/tests/Graph/EloquentTest.php
@@ -9,7 +9,7 @@ class EloquentTest extends TestCase
 {
     public function testScopeSubgraph()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -22,7 +22,7 @@ public function testScopeSubgraph()
 
     public function testScopeSubgraphWithMaxDepth()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -53,7 +53,7 @@ public function testChildren()
 
     public function testChildrenAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -82,7 +82,7 @@ public function testParents()
 
     public function testParentsAndSelf()
     {
-        if ($this->connection === 'sqlsrv') {
+        if (in_array($this->connection, ['sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -114,6 +114,10 @@ public function testScopeBreadthFirst()
 
     public function testScopeDepthFirst()
     {
+        if ($this->connection === 'firebird') {
+            $this->markTestSkipped();
+        }
+
         $nodes = Node::find(1)->descendants()->depthFirst()->get();
 
         $this->assertEquals([2, 5, 7, 8, 8, 3, 6, 4, 5, 7, 8, 8], $nodes->pluck('id')->all());
diff --git a/tests/Graph/Models/Node.php b/tests/Graph/Models/Node.php
index 273d678..cc54f3c 100644
--- a/tests/Graph/Models/Node.php
+++ b/tests/Graph/Models/Node.php
@@ -22,6 +22,8 @@ class Node extends Model
     use HasTableAlias;
     use SoftDeletes;
 
+    public $incrementing = false;
+
     protected $table = 'nodes';
 
     public function getPivotTableName(): string
@@ -41,7 +43,9 @@ public function getCustomPaths(): array
                 ],
                 [
                     'name' => 'reverse_slug_path',
-                    'column' => new Expression('nodes.slug'),
+                    'column' => new Expression(
+                        $this->newQuery()->getGrammar()->wrap('nodes.slug')
+                    ),
                     'separator' => '/',
                     'reverse' => true,
                 ],
diff --git a/tests/Graph/Models/Post.php b/tests/Graph/Models/Post.php
index aa5eac6..b9594b3 100644
--- a/tests/Graph/Models/Post.php
+++ b/tests/Graph/Models/Post.php
@@ -15,6 +15,8 @@ class Post extends Model
     use QueriesExpressions;
     use SoftDeletes;
 
+    public $incrementing = false;
+
     public function node(): BelongsTo
     {
         return $this->belongsTo(Node::class);
diff --git a/tests/Graph/TestCase.php b/tests/Graph/TestCase.php
index 3d442e8..238336b 100644
--- a/tests/Graph/TestCase.php
+++ b/tests/Graph/TestCase.php
@@ -3,6 +3,7 @@
 namespace Staudenmeir\LaravelAdjacencyList\Tests\Graph;
 
 use Carbon\Carbon;
+use HarryGulliford\Firebird\FirebirdServiceProvider;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Support\Facades\DB;
@@ -43,12 +44,14 @@ protected function tearDown(): void
 
     protected function migrateDatabase(): void
     {
-        Schema::dropAllTables();
+        Schema::dropIfExists('nodes');
+        Schema::dropIfExists('edges');
+        Schema::dropIfExists('posts');
 
         Schema::create(
             'nodes',
             function (Blueprint $table) {
-                $table->id();
+                $table->unsignedBigInteger('id')->unique();
                 $table->string('slug')->unique();
                 $table->uuid()->unique();
                 $table->timestamps();
@@ -73,7 +76,7 @@ function (Blueprint $table) {
         Schema::create(
             'posts',
             function (Blueprint $table) {
-                $table->unsignedInteger('id');
+                $table->unsignedInteger('id')->unique();
                 $table->unsignedInteger('node_id');
                 $table->timestamps();
                 $table->softDeletes();
@@ -89,142 +92,138 @@ protected function seedDatabase(): void
 
         Model::unguard();
 
-        Node::create(['slug' => 'node-1', 'uuid' => 'a0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-2', 'uuid' => 'b0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-3', 'uuid' => 'c0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-4', 'uuid' => 'd0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-5', 'uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-6', 'uuid' => 'f0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-7', 'uuid' => 'a1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-8', 'uuid' => 'b1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-9', 'uuid' => 'c1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-10', 'uuid' => 'd1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-11', 'uuid' => 'e1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b', 'deleted_at' => Carbon::now()]);
-
-        DB::table('edges')->insert(
-            [
-                [
-                    'parent_id' => 1,
-                    'child_id' => 2,
-                    'parent_uuid' => 'a0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'b0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'a',
-                    'weight' => 1,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 1,
-                    'child_id' => 3,
-                    'parent_uuid' => 'a0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'c0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'b',
-                    'weight' => 2,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 1,
-                    'child_id' => 4,
-                    'parent_uuid' => 'a0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'd0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'c',
-                    'weight' => 3,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 1,
-                    'child_id' => 5,
-                    'parent_uuid' => 'a0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'd',
-                    'weight' => 4,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 2,
-                    'child_id' => 5,
-                    'parent_uuid' => 'b0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'e',
-                    'weight' => 5,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 3,
-                    'child_id' => 6,
-                    'parent_uuid' => 'c0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'f0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'f',
-                    'weight' => 6,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 5,
-                    'child_id' => 7,
-                    'parent_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'a1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'g',
-                    'weight' => 7,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 5,
-                    'child_id' => 8,
-                    'parent_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'b1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'h',
-                    'weight' => 8,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 7,
-                    'child_id' => 8,
-                    'parent_uuid' => 'a1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'b1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'i',
-                    'weight' => 9,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 9,
-                    'child_id' => 2,
-                    'parent_uuid' => 'c1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'b0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'j',
-                    'weight' => 10,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 10,
-                    'child_id' => 5,
-                    'parent_uuid' => 'd1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'k',
-                    'weight' => 11,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 11,
-                    'child_id' => 5,
-                    'parent_uuid' => 'e1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'l',
-                    'weight' => 12,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-            ]
-        );
+        Node::create(['id' => 1, 'slug' => 'node-1', 'uuid' => 'a0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 2, 'slug' => 'node-2', 'uuid' => 'b0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 3, 'slug' => 'node-3', 'uuid' => 'c0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 4, 'slug' => 'node-4', 'uuid' => 'd0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 5, 'slug' => 'node-5', 'uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 6, 'slug' => 'node-6', 'uuid' => 'f0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 7, 'slug' => 'node-7', 'uuid' => 'a1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 8, 'slug' => 'node-8', 'uuid' => 'b1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 9, 'slug' => 'node-9', 'uuid' => 'c1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 10, 'slug' => 'node-10', 'uuid' => 'd1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 11, 'slug' => 'node-11', 'uuid' => 'e1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b', 'deleted_at' => Carbon::now()]);
+
+        DB::table('edges')->insert([
+            'parent_id' => 1,
+            'child_id' => 2,
+            'parent_uuid' => 'a0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'b0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'a',
+            'weight' => 1,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 1,
+            'child_id' => 3,
+            'parent_uuid' => 'a0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'c0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'b',
+            'weight' => 2,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 1,
+            'child_id' => 4,
+            'parent_uuid' => 'a0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'd0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'c',
+            'weight' => 3,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 1,
+            'child_id' => 5,
+            'parent_uuid' => 'a0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'd',
+            'weight' => 4,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 2,
+            'child_id' => 5,
+            'parent_uuid' => 'b0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'e',
+            'weight' => 5,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 3,
+            'child_id' => 6,
+            'parent_uuid' => 'c0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'f0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'f',
+            'weight' => 6,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 5,
+            'child_id' => 7,
+            'parent_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'a1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'g',
+            'weight' => 7,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 5,
+            'child_id' => 8,
+            'parent_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'b1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'h',
+            'weight' => 8,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 7,
+            'child_id' => 8,
+            'parent_uuid' => 'a1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'b1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'i',
+            'weight' => 9,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 9,
+            'child_id' => 2,
+            'parent_uuid' => 'c1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'b0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'j',
+            'weight' => 10,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 10,
+            'child_id' => 5,
+            'parent_uuid' => 'd1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'k',
+            'weight' => 11,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 11,
+            'child_id' => 5,
+            'parent_uuid' => 'e1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'e0f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'l',
+            'weight' => 12,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
 
         Post::create(['id' => 101, 'node_id' => 1, 'deleted_at' => null]);
         Post::create(['id' => 102, 'node_id' => 2, 'deleted_at' => null]);
@@ -244,45 +243,40 @@ protected function seedCycle(): void
     {
         Model::unguard();
 
-        Node::create(['slug' => 'node-12', 'uuid' => 'f1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-13', 'uuid' => 'a2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-        Node::create(['slug' => 'node-14', 'uuid' => 'b2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
-
-        DB::table('edges')->insert(
-            [
-
-                [
-                    'parent_id' => 12,
-                    'child_id' => 13,
-                    'parent_uuid' => 'f1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'a2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'm',
-                    'weight' => 13,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 13,
-                    'child_id' => 14,
-                    'parent_uuid' => 'a2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'b2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'n',
-                    'weight' => 14,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-                [
-                    'parent_id' => 14,
-                    'child_id' => 12,
-                    'parent_uuid' => 'b2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'child_uuid' => 'f1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
-                    'label' => 'o',
-                    'weight' => 15,
-                    'value' => '123.456',
-                    'created_at' => Carbon::now(),
-                ],
-            ]
-        );
+        Node::create(['id' => 12, 'slug' => 'node-12', 'uuid' => 'f1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 13, 'slug' => 'node-13', 'uuid' => 'a2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+        Node::create(['id' => 14, 'slug' => 'node-14', 'uuid' => 'b2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b']);
+
+        DB::table('edges')->insert([
+            'parent_id' => 12,
+            'child_id' => 13,
+            'parent_uuid' => 'f1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'a2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'm',
+            'weight' => 13,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 13,
+            'child_id' => 14,
+            'parent_uuid' => 'a2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'b2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'n',
+            'weight' => 14,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
+        DB::table('edges')->insert([
+            'parent_id' => 14,
+            'child_id' => 12,
+            'parent_uuid' => 'b2f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'child_uuid' => 'f1f1b2c3-d4e5-4f6a-8b9b-0c1d2e3f4a5b',
+            'label' => 'o',
+            'weight' => 15,
+            'value' => '123.456',
+            'created_at' => Carbon::now(),
+        ]);
 
         Model::reguard();
     }
@@ -318,4 +312,9 @@ protected function getEnvironmentSetUp($app)
 
         $app['config']->set('database.connections.testing', $config[$this->connection]);
     }
+
+    protected function getPackageProviders($app)
+    {
+        return [FirebirdServiceProvider::class];
+    }
 }
diff --git a/tests/Tree/AncestorsTest.php b/tests/Tree/AncestorsTest.php
index 2b7d145..7374a7c 100644
--- a/tests/Tree/AncestorsTest.php
+++ b/tests/Tree/AncestorsTest.php
@@ -2,6 +2,7 @@
 
 namespace Staudenmeir\LaravelAdjacencyList\Tests\Tree;
 
+use Illuminate\Support\Facades\DB;
 use Staudenmeir\LaravelAdjacencyList\Eloquent\Relations\Ancestors;
 use Staudenmeir\LaravelAdjacencyList\Tests\Tree\Models\User;
 
@@ -102,7 +103,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -113,7 +114,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -124,7 +125,7 @@ public function testExistenceQueryAndSelf()
 
     public function testExistenceQueryForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -135,7 +136,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testExistenceQueryForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -146,7 +147,7 @@ public function testExistenceQueryForSelfRelationAndSelf()
 
     public function testWithSumForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -157,7 +158,7 @@ public function testWithSumForSelfRelation()
 
     public function testWithSumForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -168,7 +169,7 @@ public function testWithSumForSelfRelationAndSelf()
 
     public function testUpdate()
     {
-        if (in_array($this->connection, ['mariadb', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/BelongsToManyOfDescendantsTest.php b/tests/Tree/BelongsToManyOfDescendantsTest.php
index 16c45b8..1d1903c 100644
--- a/tests/Tree/BelongsToManyOfDescendantsTest.php
+++ b/tests/Tree/BelongsToManyOfDescendantsTest.php
@@ -87,7 +87,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -98,7 +98,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -109,7 +109,7 @@ public function testExistenceQueryAndSelf()
 
     public function testExistenceQueryForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -120,7 +120,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testExistenceQueryForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -131,7 +131,7 @@ public function testExistenceQueryForSelfRelationAndSelf()
 
     public function testDelete()
     {
-        if ($this->connection === 'mariadb') {
+        if (in_array($this->connection, ['mariadb', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -144,7 +144,7 @@ public function testDelete()
 
     public function testDeleteAndSelf()
     {
-        if ($this->connection === 'mariadb') {
+        if (in_array($this->connection, ['mariadb', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/BloodlineTest.php b/tests/Tree/BloodlineTest.php
index ce2ec90..a96ec63 100644
--- a/tests/Tree/BloodlineTest.php
+++ b/tests/Tree/BloodlineTest.php
@@ -45,7 +45,7 @@ public function testLazyEagerLoading()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -56,7 +56,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -67,7 +67,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testIncrement()
     {
-        if (in_array($this->connection, ['mariadb', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -81,7 +81,7 @@ public function testIncrement()
 
     public function testDecrement()
     {
-        if (in_array($this->connection, ['mariadb', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/Concatenation/AncestorsTest.php b/tests/Tree/Concatenation/AncestorsTest.php
index b89aa6d..6c08558 100644
--- a/tests/Tree/Concatenation/AncestorsTest.php
+++ b/tests/Tree/Concatenation/AncestorsTest.php
@@ -92,7 +92,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -103,7 +103,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/Concatenation/BloodlineTest.php b/tests/Tree/Concatenation/BloodlineTest.php
index 839bf83..755b469 100644
--- a/tests/Tree/Concatenation/BloodlineTest.php
+++ b/tests/Tree/Concatenation/BloodlineTest.php
@@ -47,7 +47,7 @@ public function testLazyEagerLoading()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/Concatenation/DescendantsTest.php b/tests/Tree/Concatenation/DescendantsTest.php
index ce83063..78eb8f5 100644
--- a/tests/Tree/Concatenation/DescendantsTest.php
+++ b/tests/Tree/Concatenation/DescendantsTest.php
@@ -93,7 +93,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -104,7 +104,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/DescendantsTest.php b/tests/Tree/DescendantsTest.php
index fa47785..292ee54 100644
--- a/tests/Tree/DescendantsTest.php
+++ b/tests/Tree/DescendantsTest.php
@@ -2,6 +2,7 @@
 
 namespace Staudenmeir\LaravelAdjacencyList\Tests\Tree;
 
+use Illuminate\Support\Facades\DB;
 use Staudenmeir\LaravelAdjacencyList\Eloquent\Relations\Descendants;
 use Staudenmeir\LaravelAdjacencyList\Tests\Tree\Models\User;
 
@@ -9,8 +10,12 @@ class DescendantsTest extends TestCase
 {
     public function testLazyLoading()
     {
+        DB::connection()->enableQueryLog();
+
         $descendants = User::find(2)->descendants;
 
+        //dd(DB::getQueryLog());
+
         $this->assertEquals([5, 8], $descendants->pluck('id')->all());
         $this->assertEquals([1, 2], $descendants->pluck('depth')->all());
         $this->assertEquals(['5', '5.8'], $descendants->pluck('path')->all());
@@ -92,7 +97,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -103,7 +108,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -114,7 +119,7 @@ public function testExistenceQueryAndSelf()
 
     public function testExistenceQueryForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -125,7 +130,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testExistenceQueryForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -136,7 +141,7 @@ public function testExistenceQueryForSelfRelationAndSelf()
 
     public function testWithSumForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -147,7 +152,7 @@ public function testWithSumForSelfRelation()
 
     public function testWithSumForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -158,7 +163,7 @@ public function testWithSumForSelfRelationAndSelf()
 
     public function testDelete()
     {
-        if (in_array($this->connection, ['mariadb', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -171,7 +176,7 @@ public function testDelete()
 
     public function testForceDelete()
     {
-        if (in_array($this->connection, ['mariadb', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/EloquentTest.php b/tests/Tree/EloquentTest.php
index 1e3d728..25c74bc 100644
--- a/tests/Tree/EloquentTest.php
+++ b/tests/Tree/EloquentTest.php
@@ -158,6 +158,10 @@ public function testScopeBreadthFirst()
 
     public function testScopeDepthFirst()
     {
+        if ($this->connection === 'firebird') {
+            $this->markTestSkipped();
+        }
+
         $users = User::tree()->depthFirst()->get();
 
         $this->assertEquals([1, 2, 5, 8, 3, 6, 9, 4, 7, 11, 12], $users->pluck('id')->all());
@@ -165,11 +169,11 @@ public function testScopeDepthFirst()
 
     public function testScopeDepthFirstWithNaturalSorting()
     {
-        if (in_array($this->connection, ['sqlite', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['sqlite', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
-        User::forceCreate(['id' => 70, 'slug' => 'user-70', 'parent_id' => 5, 'deleted_at' => null]);
+        User::forceCreate(['id' => 70, 'slug' => 'user-70', 'parent_id' => 5, 'followers' => 1, 'deleted_at' => null]);
 
         $users = User::tree()->depthFirst()->get();
 
@@ -178,6 +182,10 @@ public function testScopeDepthFirstWithNaturalSorting()
 
     public function testScopeDepthFirstWithStringKey()
     {
+        if ($this->connection === 'firebird') {
+            $this->markTestSkipped();
+        }
+
         $categories = Category::tree()->depthFirst()->get();
 
         $this->assertEquals(['a', 'b', 'c', 'd'], $categories->pluck('id')->all());
diff --git a/tests/Tree/HasManyOfDescendantsTest.php b/tests/Tree/HasManyOfDescendantsTest.php
index 04e2133..a8aebcb 100644
--- a/tests/Tree/HasManyOfDescendantsTest.php
+++ b/tests/Tree/HasManyOfDescendantsTest.php
@@ -3,6 +3,7 @@
 namespace Staudenmeir\LaravelAdjacencyList\Tests\Tree;
 
 use Illuminate\Database\Eloquent\SoftDeletingScope;
+use Illuminate\Support\Facades\DB;
 use Staudenmeir\LaravelAdjacencyList\Eloquent\Relations\HasManyOfDescendants;
 use Staudenmeir\LaravelAdjacencyList\Tests\Scopes\DepthScope;
 use Staudenmeir\LaravelAdjacencyList\Tests\Tree\Models\Post;
@@ -104,7 +105,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -115,7 +116,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -126,7 +127,7 @@ public function testExistenceQueryAndSelf()
 
     public function testExistenceQueryForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -137,7 +138,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testExistenceQueryForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -148,7 +149,7 @@ public function testExistenceQueryForSelfRelationAndSelf()
 
     public function testUpdate()
     {
-        if ($this->connection === 'mariadb') {
+        if (in_array($this->connection, ['mariadb', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -161,7 +162,7 @@ public function testUpdate()
 
     public function testUpdateAndSelf()
     {
-        if ($this->connection === 'mariadb') {
+        if (in_array($this->connection, ['mariadb', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/Models/Post.php b/tests/Tree/Models/Post.php
index 47b62bf..27d6c83 100644
--- a/tests/Tree/Models/Post.php
+++ b/tests/Tree/Models/Post.php
@@ -10,4 +10,6 @@ class Post extends Model
 {
     use QueriesExpressions;
     use SoftDeletes;
+
+    public $incrementing = false;
 }
diff --git a/tests/Tree/Models/Role.php b/tests/Tree/Models/Role.php
index 0b2ac3b..03a8e5c 100644
--- a/tests/Tree/Models/Role.php
+++ b/tests/Tree/Models/Role.php
@@ -15,6 +15,8 @@ class Role extends Model
     use QueriesExpressions;
     use SoftDeletes;
 
+    public $incrementing = false;
+
     public function userAncestors(): HasManyDeep
     {
         return $this->hasManyDeepFromRelations(
diff --git a/tests/Tree/Models/Tag.php b/tests/Tree/Models/Tag.php
index f9b188c..3ded267 100644
--- a/tests/Tree/Models/Tag.php
+++ b/tests/Tree/Models/Tag.php
@@ -10,4 +10,6 @@ class Tag extends Model
 {
     use QueriesExpressions;
     use SoftDeletes;
+
+    public $incrementing = false;
 }
diff --git a/tests/Tree/Models/User.php b/tests/Tree/Models/User.php
index 2fa5e7f..cff17e3 100644
--- a/tests/Tree/Models/User.php
+++ b/tests/Tree/Models/User.php
@@ -23,6 +23,12 @@ class User extends Model
     use HasTableAlias;
     use SoftDeletes;
 
+    public $incrementing = false;
+
+    protected $casts = [
+        'id' => 'int',
+    ];
+
     public function getCustomPaths(): array
     {
         return array_merge(
@@ -35,7 +41,9 @@ public function getCustomPaths(): array
                 ],
                 [
                     'name' => 'reverse_slug_path',
-                    'column' => new Expression('users.slug'),
+                    'column' => new Expression(
+                        $this->newQuery()->getGrammar()->wrap('users.slug')
+                    ),
                     'separator' => '/',
                     'reverse' => true,
                 ],
diff --git a/tests/Tree/Models/Video.php b/tests/Tree/Models/Video.php
index 393b3be..fc48d50 100644
--- a/tests/Tree/Models/Video.php
+++ b/tests/Tree/Models/Video.php
@@ -10,4 +10,6 @@ class Video extends Model
 {
     use QueriesExpressions;
     use SoftDeletes;
+
+    public $incrementing = false;
 }
diff --git a/tests/Tree/MorphToManyOfDescendantsTest.php b/tests/Tree/MorphToManyOfDescendantsTest.php
index 8131ecc..67d771a 100644
--- a/tests/Tree/MorphToManyOfDescendantsTest.php
+++ b/tests/Tree/MorphToManyOfDescendantsTest.php
@@ -87,7 +87,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -98,7 +98,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -109,7 +109,7 @@ public function testExistenceQueryAndSelf()
 
     public function testExistenceQueryForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -120,7 +120,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testExistenceQueryForSelfRelationAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -131,7 +131,7 @@ public function testExistenceQueryForSelfRelationAndSelf()
 
     public function testDelete()
     {
-        if ($this->connection === 'mariadb') {
+        if (in_array($this->connection, ['mariadb', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -144,7 +144,7 @@ public function testDelete()
 
     public function testDeleteAndSelf()
     {
-        if ($this->connection === 'mariadb') {
+        if (in_array($this->connection, ['mariadb', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/MorphedByManyOfDescendantsTest.php b/tests/Tree/MorphedByManyOfDescendantsTest.php
index 08bd5a6..e031f23 100644
--- a/tests/Tree/MorphedByManyOfDescendantsTest.php
+++ b/tests/Tree/MorphedByManyOfDescendantsTest.php
@@ -87,7 +87,7 @@ public function testLazyEagerLoadingAndSelf()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -98,7 +98,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryAndSelf()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -109,7 +109,7 @@ public function testExistenceQueryAndSelf()
 
     public function testExistenceQueryForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -131,7 +131,7 @@ public function testExistenceQueryForSelfRelationAndSelf()
 
     public function testDelete()
     {
-        if ($this->connection === 'mariadb') {
+        if (in_array($this->connection, ['mariadb', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -144,7 +144,7 @@ public function testDelete()
 
     public function testDeleteAndSelf()
     {
-        if ($this->connection === 'mariadb') {
+        if (in_array($this->connection, ['mariadb', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/RootAncestorOrSelfTest.php b/tests/Tree/RootAncestorOrSelfTest.php
index 4688250..e2de851 100644
--- a/tests/Tree/RootAncestorOrSelfTest.php
+++ b/tests/Tree/RootAncestorOrSelfTest.php
@@ -42,7 +42,7 @@ public function testLazyEagerLoading()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -53,7 +53,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -64,7 +64,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testUpdate()
     {
-        if (in_array($this->connection, ['mariadb', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/RootAncestorTest.php b/tests/Tree/RootAncestorTest.php
index 5480d49..9119bb9 100644
--- a/tests/Tree/RootAncestorTest.php
+++ b/tests/Tree/RootAncestorTest.php
@@ -39,7 +39,7 @@ public function testLazyEagerLoading()
 
     public function testExistenceQuery()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -50,7 +50,7 @@ public function testExistenceQuery()
 
     public function testExistenceQueryForSelfRelation()
     {
-        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'sqlsrv', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
@@ -61,7 +61,7 @@ public function testExistenceQueryForSelfRelation()
 
     public function testUpdate()
     {
-        if (in_array($this->connection, ['mariadb', 'singlestore'])) {
+        if (in_array($this->connection, ['mariadb', 'singlestore', 'firebird'])) {
             $this->markTestSkipped();
         }
 
diff --git a/tests/Tree/TestCase.php b/tests/Tree/TestCase.php
index 6fa24f2..32261ad 100644
--- a/tests/Tree/TestCase.php
+++ b/tests/Tree/TestCase.php
@@ -3,6 +3,7 @@
 namespace Staudenmeir\LaravelAdjacencyList\Tests\Tree;
 
 use Carbon\Carbon;
+use HarryGulliford\Firebird\FirebirdServiceProvider;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Support\Facades\DB;
@@ -40,36 +41,56 @@ protected function tearDown(): void
 
     protected function migrateDatabase(): void
     {
-        Schema::dropAllTables();
+        Schema::dropIfExists('users');
+        Schema::dropIfExists('posts');
+        Schema::dropIfExists('roles');
+        Schema::dropIfExists('role_user');
+        Schema::dropIfExists('tags');
+        Schema::dropIfExists('taggables');
+        Schema::dropIfExists('videos');
+        Schema::dropIfExists('authorables');
+        Schema::dropIfExists('categories');
 
         Schema::create(
             'users',
             function (Blueprint $table) {
-                $table->id();
+                $table->unsignedBigInteger('id')->unique();
                 $table->string('slug');
-                $table->unsignedInteger('parent_id')->nullable();
-                $table->unsignedBigInteger('followers')->default(1);
+                $table->unsignedBigInteger('parent_id')->nullable();
+                $table->unsignedBigInteger('followers');
                 $table->timestamps();
                 $table->softDeletes();
+
+                if ($this->connection === 'singlestore') {
+                    $table->shardKey('id');
+                }
             }
         );
 
         Schema::create(
             'posts',
             function (Blueprint $table) {
-                $table->unsignedInteger('id');
-                $table->unsignedInteger('user_id');
+                $table->unsignedBigInteger('id')->unique();
+                $table->unsignedBigInteger('user_id');
                 $table->timestamps();
                 $table->softDeletes();
+
+                if ($this->connection === 'singlestore') {
+                    $table->shardKey('id');
+                }
             }
         );
 
         Schema::create(
             'roles',
             function (Blueprint $table) {
-                $table->unsignedInteger('id');
+                $table->unsignedBigInteger('id')->unique();
                 $table->timestamps();
                 $table->softDeletes();
+
+                if ($this->connection === 'singlestore') {
+                    $table->shardKey('id');
+                }
             }
         );
 
@@ -84,16 +105,20 @@ function (Blueprint $table) {
         Schema::create(
             'tags',
             function (Blueprint $table) {
-                $table->unsignedInteger('id');
+                $table->unsignedBigInteger('id')->unique();
                 $table->timestamps();
                 $table->softDeletes();
+
+                if ($this->connection === 'singlestore') {
+                    $table->shardKey('id');
+                }
             }
         );
 
         Schema::create(
             'taggables',
             function (Blueprint $table) {
-                $table->unsignedInteger('tag_id');
+                $table->unsignedBigInteger('tag_id');
                 $table->morphs('taggable');
             }
         );
@@ -101,16 +126,20 @@ function (Blueprint $table) {
         Schema::create(
             'videos',
             function (Blueprint $table) {
-                $table->unsignedInteger('id');
+                $table->unsignedBigInteger('id')->unique();
                 $table->timestamps();
                 $table->softDeletes();
+
+                if ($this->connection === 'singlestore') {
+                    $table->shardKey('id');
+                }
             }
         );
 
         Schema::create(
             'authorables',
             function (Blueprint $table) {
-                $table->unsignedInteger('user_id');
+                $table->unsignedBigInteger('user_id');
                 $table->morphs('authorable');
             }
         );
@@ -118,9 +147,13 @@ function (Blueprint $table) {
         Schema::create(
             'categories',
             function (Blueprint $table) {
-                $table->string('id');
+                $table->string('id')->unique();
                 $table->string('parent_id')->nullable();
                 $table->timestamps();
+
+                if ($this->connection === 'singlestore') {
+                    $table->shardKey('id');
+                }
             }
         );
     }
@@ -129,18 +162,18 @@ protected function seedDatabase(): void
     {
         Model::unguard();
 
-        User::create(['slug' => 'user-1', 'parent_id' => null, 'deleted_at' => null]);
-        User::create(['slug' => 'user-2', 'parent_id' => 1, 'deleted_at' => null]);
-        User::create(['slug' => 'user-3', 'parent_id' => 1, 'deleted_at' => null]);
-        User::create(['slug' => 'user-4', 'parent_id' => 1, 'deleted_at' => null]);
-        User::create(['slug' => 'user-5', 'parent_id' => 2, 'deleted_at' => null]);
-        User::create(['slug' => 'user-6', 'parent_id' => 3, 'deleted_at' => null]);
-        User::create(['slug' => 'user-7', 'parent_id' => 4, 'deleted_at' => null]);
-        User::create(['slug' => 'user-8', 'parent_id' => 5, 'deleted_at' => null]);
-        User::create(['slug' => 'user-9', 'parent_id' => 6, 'deleted_at' => null]);
-        User::create(['slug' => 'user-10', 'parent_id' => 7, 'deleted_at' => Carbon::now()]);
-        User::create(['slug' => 'user-11', 'parent_id' => null, 'deleted_at' => null]);
-        User::create(['slug' => 'user-12', 'parent_id' => 11, 'deleted_at' => null]);
+        User::create(['id' => 1, 'slug' => 'user-1', 'parent_id' => null, 'followers' => 1, 'deleted_at' => null]);
+        User::create(['id' => 2, 'slug' => 'user-2', 'parent_id' => 1, 'followers' => 1, 'deleted_at' => null]);
+        User::create(['id' => 3, 'slug' => 'user-3', 'parent_id' => 1, 'followers' => 1, 'deleted_at' => null]);
+        User::create(['id' => 4, 'slug' => 'user-4', 'parent_id' => 1, 'followers' => 1, 'deleted_at' => null]);
+        User::create(['id' => 5, 'slug' => 'user-5', 'parent_id' => 2, 'followers' => 1, 'deleted_at' => null]);
+        User::create(['id' => 6, 'slug' => 'user-6', 'parent_id' => 3, 'followers' => 1, 'deleted_at' => null]);
+        User::create(['id' => 7, 'slug' => 'user-7', 'parent_id' => 4, 'followers' => 1, 'deleted_at' => null]);
+        User::create(['id' => 8, 'slug' => 'user-8', 'parent_id' => 5, 'followers' => 1, 'deleted_at' => null]);
+        User::create(['id' => 9, 'slug' => 'user-9', 'parent_id' => 6, 'followers' => 1, 'deleted_at' => null]);
+        User::create(['id' => 10, 'slug' => 'user-10', 'parent_id' => 7, 'followers' => 1, 'deleted_at' => Carbon::now()]);
+        User::create(['id' => 11, 'slug' => 'user-11', 'parent_id' => null, 'followers' => 1, 'deleted_at' => null]);
+        User::create(['id' => 12, 'slug' => 'user-12', 'parent_id' => 11, 'followers' => 1, 'deleted_at' => null]);
 
         Post::create(['id' => 10, 'user_id' => 1, 'deleted_at' => null]);
         Post::create(['id' => 20, 'user_id' => 2, 'deleted_at' => null]);
@@ -168,22 +201,18 @@ protected function seedDatabase(): void
         Role::create(['id' => 111, 'deleted_at' => null]);
         Role::create(['id' => 121, 'deleted_at' => Carbon::now()]);
 
-        DB::table('role_user')->insert(
-            [
-                ['role_id' => 11, 'user_id' => 1],
-                ['role_id' => 21, 'user_id' => 2],
-                ['role_id' => 31, 'user_id' => 3],
-                ['role_id' => 41, 'user_id' => 4],
-                ['role_id' => 51, 'user_id' => 5],
-                ['role_id' => 61, 'user_id' => 6],
-                ['role_id' => 71, 'user_id' => 7],
-                ['role_id' => 81, 'user_id' => 8],
-                ['role_id' => 91, 'user_id' => 10],
-                ['role_id' => 101, 'user_id' => 12],
-                ['role_id' => 111, 'user_id' => 12],
-                ['role_id' => 121, 'user_id' => 12],
-            ]
-        );
+        DB::table('role_user')->insert(['role_id' => 11, 'user_id' => 1]);
+        DB::table('role_user')->insert(['role_id' => 21, 'user_id' => 2]);
+        DB::table('role_user')->insert(['role_id' => 31, 'user_id' => 3]);
+        DB::table('role_user')->insert(['role_id' => 41, 'user_id' => 4]);
+        DB::table('role_user')->insert(['role_id' => 51, 'user_id' => 5]);
+        DB::table('role_user')->insert(['role_id' => 61, 'user_id' => 6]);
+        DB::table('role_user')->insert(['role_id' => 71, 'user_id' => 7]);
+        DB::table('role_user')->insert(['role_id' => 81, 'user_id' => 8]);
+        DB::table('role_user')->insert(['role_id' => 91, 'user_id' => 10]);
+        DB::table('role_user')->insert(['role_id' => 101, 'user_id' => 12]);
+        DB::table('role_user')->insert(['role_id' => 111, 'user_id' => 12]);
+        DB::table('role_user')->insert(['role_id' => 121, 'user_id' => 12]);
 
         Tag::create(['id' => 12, 'deleted_at' => null]);
         Tag::create(['id' => 22, 'deleted_at' => null]);
@@ -198,23 +227,19 @@ protected function seedDatabase(): void
         Tag::create(['id' => 112, 'deleted_at' => null]);
         Tag::create(['id' => 122, 'deleted_at' => Carbon::now()]);
 
-        DB::table('taggables')->insert(
-            [
-                ['tag_id' => 12, 'taggable_type' => User::class, 'taggable_id' => 1],
-                ['tag_id' => 22, 'taggable_type' => User::class, 'taggable_id' => 2],
-                ['tag_id' => 32, 'taggable_type' => User::class, 'taggable_id' => 3],
-                ['tag_id' => 42, 'taggable_type' => User::class, 'taggable_id' => 4],
-                ['tag_id' => 52, 'taggable_type' => User::class, 'taggable_id' => 5],
-                ['tag_id' => 62, 'taggable_type' => User::class, 'taggable_id' => 6],
-                ['tag_id' => 72, 'taggable_type' => User::class, 'taggable_id' => 7],
-                ['tag_id' => 82, 'taggable_type' => User::class, 'taggable_id' => 8],
-                ['tag_id' => 92, 'taggable_type' => User::class, 'taggable_id' => 10],
-                ['tag_id' => 102, 'taggable_type' => User::class, 'taggable_id' => 12],
-                ['tag_id' => 112, 'taggable_type' => User::class, 'taggable_id' => 12],
-                ['tag_id' => 122, 'taggable_type' => User::class, 'taggable_id' => 12],
-                ['tag_id' => 12, 'taggable_type' => Post::class, 'taggable_id' => 5],
-            ]
-        );
+        DB::table('taggables')->insert(['tag_id' => 12, 'taggable_type' => User::class, 'taggable_id' => 1]);
+        DB::table('taggables')->insert(['tag_id' => 22, 'taggable_type' => User::class, 'taggable_id' => 2]);
+        DB::table('taggables')->insert(['tag_id' => 32, 'taggable_type' => User::class, 'taggable_id' => 3]);
+        DB::table('taggables')->insert(['tag_id' => 42, 'taggable_type' => User::class, 'taggable_id' => 4]);
+        DB::table('taggables')->insert(['tag_id' => 52, 'taggable_type' => User::class, 'taggable_id' => 5]);
+        DB::table('taggables')->insert(['tag_id' => 62, 'taggable_type' => User::class, 'taggable_id' => 6]);
+        DB::table('taggables')->insert(['tag_id' => 72, 'taggable_type' => User::class, 'taggable_id' => 7]);
+        DB::table('taggables')->insert(['tag_id' => 82, 'taggable_type' => User::class, 'taggable_id' => 8]);
+        DB::table('taggables')->insert(['tag_id' => 92, 'taggable_type' => User::class, 'taggable_id' => 10]);
+        DB::table('taggables')->insert(['tag_id' => 102, 'taggable_type' => User::class, 'taggable_id' => 12]);
+        DB::table('taggables')->insert(['tag_id' => 112, 'taggable_type' => User::class, 'taggable_id' => 12]);
+        DB::table('taggables')->insert(['tag_id' => 122, 'taggable_type' => User::class, 'taggable_id' => 12]);
+        DB::table('taggables')->insert(['tag_id' => 12, 'taggable_type' => Post::class, 'taggable_id' => 5]);
 
         Video::create(['id' => 13, 'deleted_at' => null]);
         Video::create(['id' => 23, 'deleted_at' => null]);
@@ -229,23 +254,19 @@ protected function seedDatabase(): void
         Video::create(['id' => 113, 'deleted_at' => null]);
         Video::create(['id' => 123, 'deleted_at' => Carbon::now()]);
 
-        DB::table('authorables')->insert(
-            [
-                ['user_id' => 1, 'authorable_type' => Video::class, 'authorable_id' => 13],
-                ['user_id' => 2, 'authorable_type' => Video::class, 'authorable_id' => 23],
-                ['user_id' => 3, 'authorable_type' => Video::class, 'authorable_id' => 33],
-                ['user_id' => 4, 'authorable_type' => Video::class, 'authorable_id' => 43],
-                ['user_id' => 5, 'authorable_type' => Video::class, 'authorable_id' => 53],
-                ['user_id' => 6, 'authorable_type' => Video::class, 'authorable_id' => 63],
-                ['user_id' => 7, 'authorable_type' => Video::class, 'authorable_id' => 73],
-                ['user_id' => 8, 'authorable_type' => Video::class, 'authorable_id' => 83],
-                ['user_id' => 10, 'authorable_type' => Video::class, 'authorable_id' => 93],
-                ['user_id' => 12, 'authorable_type' => Video::class, 'authorable_id' => 103],
-                ['user_id' => 12, 'authorable_type' => Video::class, 'authorable_id' => 113],
-                ['user_id' => 12, 'authorable_type' => Video::class, 'authorable_id' => 123],
-                ['user_id' => 5, 'authorable_type' => Post::class, 'authorable_id' => 13],
-            ]
-        );
+        DB::table('authorables')->insert(['user_id' => 1, 'authorable_type' => Video::class, 'authorable_id' => 13]);
+        DB::table('authorables')->insert(['user_id' => 2, 'authorable_type' => Video::class, 'authorable_id' => 23]);
+        DB::table('authorables')->insert(['user_id' => 3, 'authorable_type' => Video::class, 'authorable_id' => 33]);
+        DB::table('authorables')->insert(['user_id' => 4, 'authorable_type' => Video::class, 'authorable_id' => 43]);
+        DB::table('authorables')->insert(['user_id' => 5, 'authorable_type' => Video::class, 'authorable_id' => 53]);
+        DB::table('authorables')->insert(['user_id' => 6, 'authorable_type' => Video::class, 'authorable_id' => 63]);
+        DB::table('authorables')->insert(['user_id' => 7, 'authorable_type' => Video::class, 'authorable_id' => 73]);
+        DB::table('authorables')->insert(['user_id' => 8, 'authorable_type' => Video::class, 'authorable_id' => 83]);
+        DB::table('authorables')->insert(['user_id' => 10, 'authorable_type' => Video::class, 'authorable_id' => 93]);
+        DB::table('authorables')->insert(['user_id' => 12, 'authorable_type' => Video::class, 'authorable_id' => 103]);
+        DB::table('authorables')->insert(['user_id' => 12, 'authorable_type' => Video::class, 'authorable_id' => 113]);
+        DB::table('authorables')->insert(['user_id' => 12, 'authorable_type' => Video::class, 'authorable_id' => 123]);
+        DB::table('authorables')->insert(['user_id' => 5, 'authorable_type' => Post::class, 'authorable_id' => 13]);
 
         Category::create(['id' => 'a', 'parent_id' => null]);
         Category::create(['id' => 'd', 'parent_id' => 'a']);
@@ -266,6 +287,6 @@ protected function getEnvironmentSetUp($app)
 
     protected function getPackageProviders($app)
     {
-        return [SingleStoreProvider::class];
+        return [SingleStoreProvider::class, FirebirdServiceProvider::class];
     }
 }
diff --git a/tests/config/database.php b/tests/config/database.php
index 015ff34..d826709 100644
--- a/tests/config/database.php
+++ b/tests/config/database.php
@@ -76,4 +76,14 @@
             PDO::ATTR_EMULATE_PREPARES => true,
         ]) : [],
     ],
+    'firebird' => [
+        'driver' => 'firebird',
+        'host' => 'firebird',
+        'port' => '3050',
+        'database' => '/firebird/data/test.fdb',
+        'username' => 'sysdba',
+        'password' => 'password',
+        'charset' => 'UTF8',
+        'role' => null,
+    ],
 ];