diff --git a/src/Schema/Column.php b/src/Schema/Column.php
index 4aa46d0..9a80040 100644
--- a/src/Schema/Column.php
+++ b/src/Schema/Column.php
@@ -121,7 +121,7 @@ public function opt( string $option, $value = null, $for = null )
 	 * @param bool|null $value New autoincrement flag or NULL to return current value
 	 * @return self|bool Same object for setting the value, current value without parameter
 	 */
-	public function autoincrement( bool $value = null )
+	public function autoincrement( ?bool $value = null )
 	{
 		return $this->seq( $value );
 	}
@@ -133,7 +133,7 @@ public function autoincrement( bool $value = null )
 	 * @param string|null $value New column charset or NULL to return current value
 	 * @return self|string Same object for setting the value, current value without parameter
 	 */
-	public function charset( string $value = null )
+	public function charset( ?string $value = null )
 	{
 		return $this->opt( 'charset', $value );
 	}
@@ -145,7 +145,7 @@ public function charset( string $value = null )
 	 * @param string|null $value New column collation or NULL to return current value
 	 * @return self|string Same object for setting the value, current value without parameter
 	 */
-	public function collation( string $value = null )
+	public function collation( ?string $value = null )
 	{
 		return $this->opt( 'collation', $value );
 	}
@@ -157,7 +157,7 @@ public function collation( string $value = null )
 	 * @param string|null $value New column comment or NULL to return current value
 	 * @return self|string Same object for setting the value, current value without parameter
 	 */
-	public function comment( string $value = null )
+	public function comment( ?string $value = null )
 	{
 		if( $value === null ) {
 			return $this->column->getComment();
@@ -175,7 +175,7 @@ public function comment( string $value = null )
 	 * @param array<string>|string|null $for Database type this option should be used for ("mysql", "postgresql", "sqlite", "mssql", "oracle", "db2")
 	 * @return \Aimeos\Upscheme\Schema\Column Column object
 	 */
-	public function custom( string $value = null, $for = null )
+	public function custom( ?string $value = null, $for = null )
 	{
 		if( $value === null ) {
 			return $this->column->getColumnDefinition();
@@ -212,7 +212,7 @@ public function default( $value = null )
 	 * @param bool|null $value New column fixed flag or NULL to return current value
 	 * @return self|bool Same object for setting the value, current value without parameter
 	 */
-	public function fixed( bool $value = null )
+	public function fixed( ?bool $value = null )
 	{
 		if( $value === null ) {
 			return $this->column->getFixed();
@@ -229,7 +229,7 @@ public function fixed( bool $value = null )
 	 * @param int|null $value New column length or NULL to return current value
 	 * @return self|int Same object for setting the value, current value without parameter
 	 */
-	public function length( int $value = null )
+	public function length( ?int $value = null )
 	{
 		if( $value === null ) {
 			return $this->column->getLength();
@@ -257,7 +257,7 @@ public function name() : string
 	 * @param bool|null $value New column null flag or NULL to return current value
 	 * @return self|bool Same object for setting the value, current value without parameter
 	 */
-	public function null( bool $value = null )
+	public function null( ?bool $value = null )
 	{
 		if( $value === null ) {
 			return !$this->column->getNotnull();
@@ -274,7 +274,7 @@ public function null( bool $value = null )
 	 * @param int|null $value New column precision value or NULL to return current value
 	 * @return self|int Same object for setting the value, current value without parameter
 	 */
-	public function precision( int $value = null )
+	public function precision( ?int $value = null )
 	{
 		if( $value === null ) {
 			return $this->column->getPrecision();
@@ -291,7 +291,7 @@ public function precision( int $value = null )
 	 * @param int|null $value New column scale value or NULL to return current value
 	 * @return self|int Same object for setting the value, current value without parameter
 	 */
-	public function scale( int $value = null )
+	public function scale( ?int $value = null )
 	{
 		if( $value === null ) {
 			return $this->column->getScale();
@@ -308,7 +308,7 @@ public function scale( int $value = null )
 	 * @param bool|null $value New autoincrement flag or NULL to return current value
 	 * @return self|bool Same object for setting the value, current value without parameter
 	 */
-	public function seq( bool $value = null )
+	public function seq( ?bool $value = null )
 	{
 		if( $value === null ) {
 			return $this->column->getAutoincrement();
@@ -325,7 +325,7 @@ public function seq( bool $value = null )
 	 * @param string|null $value New column type or NULL to return current value
 	 * @return self|string Same object for setting the value, current value without parameter
 	 */
-	public function type( string $value = null )
+	public function type( ?string $value = null )
 	{
 		if( $value === null )
 		{
@@ -344,7 +344,7 @@ public function type( string $value = null )
 	 * @param bool|null $value New column unsigned flag or NULL to return current value
 	 * @return self|bool Same object for setting the value, current value without parameter
 	 */
-	public function unsigned( bool $value = null )
+	public function unsigned( ?bool $value = null )
 	{
 		if( $value === null ) {
 			return $this->column->getUnsigned();
@@ -361,7 +361,7 @@ public function unsigned( bool $value = null )
 	 * @param string|null $name Name of the index or NULL to generate automatically
 	 * @return self Same object for fluid method calls
 	 */
-	public function index( string $name = null ) : self
+	public function index( ?string $name = null ) : self
 	{
 		$this->table->index( [$this->name()], $name );
 		return $this;
@@ -374,7 +374,7 @@ public function index( string $name = null ) : self
 	 * @param string|null $name Name of the index or NULL to generate automatically
 	 * @return self Same object for fluid method calls
 	 */
-	public function primary( string $name = null ) : self
+	public function primary( ?string $name = null ) : self
 	{
 		$this->table->primary( [$this->name()], $name );
 		return $this;
@@ -387,7 +387,7 @@ public function primary( string $name = null ) : self
 	 * @param string|null $name Name of the index or NULL to generate automatically
 	 * @return self Same object for fluid method calls
 	 */
-	public function spatial( string $name = null ) : self
+	public function spatial( ?string $name = null ) : self
 	{
 		$this->table->spatial( [$this->name()], $name );
 		return $this;
@@ -400,7 +400,7 @@ public function spatial( string $name = null ) : self
 	 * @param string|null $name Name of the index or NULL to generate automatically
 	 * @return self Same object for fluid method calls
 	 */
-	public function unique( string $name = null ) : self
+	public function unique( ?string $name = null ) : self
 	{
 		$this->table->unique( $this->name(), $name );
 		return $this;
diff --git a/src/Schema/DB.php b/src/Schema/DB.php
index 2c1f170..3152bbc 100644
--- a/src/Schema/DB.php
+++ b/src/Schema/DB.php
@@ -508,7 +508,7 @@ public function query( string $sql, array $params = [], array $types = [] ) : \D
 	 * @return self Same object for fluid method calls
 	 * @throws \RuntimeException If an error occured
 	 */
-	public function renameColumn( string $table, $from, string $to = null ) : self
+	public function renameColumn( string $table, $from, ?string $to = null ) : self
 	{
 		$this->up();
 		$setup = false;
@@ -546,7 +546,7 @@ public function renameColumn( string $table, $from, string $to = null ) : self
 	 * @param string|null $to New index name or NULL for autogenerated name (ignored if first parameter is an array)
 	 * @return self Same object for fluid method calls
 	 */
-	public function renameIndex( string $table, $from, string $to = null ) : self
+	public function renameIndex( string $table, $from, ?string $to = null ) : self
 	{
 		if( $this->hasTable( $table ) ) {
 			$this->table( $table )->renameIndex( $from, $to )->up();
@@ -564,7 +564,7 @@ public function renameIndex( string $table, $from, string $to = null ) : self
 	 * @return self Same object for fluid method calls
 	 * @throws \RuntimeException If an error occured
 	 */
-	public function renameTable( $from, string $to = null ) : self
+	public function renameTable( $from, ?string $to = null ) : self
 	{
 		$this->up();
 		$setup = false;
@@ -612,7 +612,7 @@ public function renameTable( $from, string $to = null ) : self
 	 * @param array<string>|null $conditions Key/value pairs of column names and value to compare with
 	 * @return array<int,array<string,mixed>> List of associative arrays containing column name/value pairs
 	 */
-	public function select( string $table, array $conditions = null ) : array
+	public function select( string $table, ?array $conditions = null ) : array
 	{
 		$idx = 0;
 		$list = [];
@@ -651,7 +651,7 @@ public function select( string $table, array $conditions = null ) : array
 	 * @param \Closure|null $fcn Anonymous function with ($sequence) parameter creating or updating the sequence definition
 	 * @return \Aimeos\Upscheme\Schema\Sequence Sequence object
 	 */
-	public function sequence( string $name, \Closure $fcn = null ) : Sequence
+	public function sequence( string $name, ?\Closure $fcn = null ) : Sequence
 	{
 		if( $this->to->hasSequence( $name ) ) {
 			$seq = $this->to->getSequence( $name );
@@ -690,7 +690,7 @@ public function stmt() : \Doctrine\DBAL\Query\QueryBuilder
 	 * @param \Closure|null $fcn Anonymous function with ($table) parameter creating or updating the table definition
 	 * @return \Aimeos\Upscheme\Schema\Table Table object
 	 */
-	public function table( string $name, \Closure $fcn = null ) : Table
+	public function table( string $name, ?\Closure $fcn = null ) : Table
 	{
 		if( $this->to->hasTable( $name ) ) {
 			$dt = $this->to->getTable( $name );
diff --git a/src/Schema/Foreign.php b/src/Schema/Foreign.php
index 773fd58..d78409f 100644
--- a/src/Schema/Foreign.php
+++ b/src/Schema/Foreign.php
@@ -74,7 +74,7 @@ class Foreign
 	 * @param array<string> $fkcol List of columns from the referenced table spawning the foreign key constraint
 	 * @param string|null $name $name Name of the foreign key constraint and index or NULL for autogenerated name
 	 */
-	public function __construct( DB $db, Table $table, DbalTable $dbaltable, array $localcol, string $fktable, array $fkcol, string $name = null )
+	public function __construct( DB $db, Table $table, DbalTable $dbaltable, array $localcol, string $fktable, array $fkcol, ?string $name = null )
 	{
 		$this->db = $db;
 		$this->table = $table;
@@ -201,7 +201,7 @@ public function name()
 	 * @param string|null $value Performed action or NULL to return current value
 	 * @return self|string Same object for setting the value, current value without parameter
 	 */
-	public function onDelete( string $value = null )
+	public function onDelete( ?string $value = null )
 	{
 		if( $value === null ) {
 			return $this->opts['onDelete'];
@@ -230,7 +230,7 @@ public function onDelete( string $value = null )
 	 * @param string|null $value Performed action or NULL to return current value
 	 * @return self|string Same object for setting the value, current value without parameter
 	 */
-	public function onUpdate( string $value = null )
+	public function onUpdate( ?string $value = null )
 	{
 		if( $value === null ) {
 			return $this->opts['onUpdate'];
@@ -264,7 +264,7 @@ public function up() : self
 	 * @param string|null $newname Name of the new constraint or same name if NULL
 	 * @return self Same object for fluid method calls
 	 */
-	protected function replace( string $newname = null ) : self
+	protected function replace( ?string $newname = null ) : self
 	{
 		$newname = $newname ?: $this->name;
 
diff --git a/src/Schema/Sequence.php b/src/Schema/Sequence.php
index cd0830f..e605814 100644
--- a/src/Schema/Sequence.php
+++ b/src/Schema/Sequence.php
@@ -91,7 +91,7 @@ public function __set( string $name, $value )
 	 * @param int $value New number of sequence IDs cached by the client or NULL to return current value
 	 * @return self|int Same object for setting value, current value without parameter
 	 */
-	public function cache( int $value = null )
+	public function cache( ?int $value = null )
 	{
 		if( $value === null ) {
 			return $this->sequence->getCache();
@@ -119,7 +119,7 @@ public function name()
 	 * @param int $value New start value of the sequence or NULL to return current value
 	 * @return self|int Same object for setting value, current value without parameter
 	 */
-	public function start( int $value = null )
+	public function start( ?int $value = null )
 	{
 		if( $value === null ) {
 			return $this->sequence->getInitialValue();
@@ -136,7 +136,7 @@ public function start( int $value = null )
 	 * @param int $value New step size the sequence is incremented or decremented by or NULL to return current value
 	 * @return self|int Same object for setting value, current value without parameter
 	 */
-	public function step( int $value = null )
+	public function step( ?int $value = null )
 	{
 		if( $value === null ) {
 			return $this->sequence->getAllocationSize();
diff --git a/src/Schema/Table.php b/src/Schema/Table.php
index 9c15f69..1d659ed 100644
--- a/src/Schema/Table.php
+++ b/src/Schema/Table.php
@@ -13,8 +13,8 @@
  * Table schema class
  *
  * @mixin \Doctrine\DBAL\Schema\Table
- * @method Schema\Column id(string $name = null)
- * @method Schema\Column bigid(string $name = null)
+ * @method Schema\Column id(?string $name = null)
+ * @method Schema\Column bigid(?string $name = null)
  */
 class Table
 {
@@ -174,7 +174,7 @@ public function char( string $name, int $length ) : Column
 	 * @param string $type|null Type of the column
 	 * @return \Aimeos\Upscheme\Schema\Column Column object
 	 */
-	public function col( string $name, string $type = null ) : Column
+	public function col( string $name, ?string $type = null ) : Column
 	{
 		if( $this->table->hasColumn( $name ) ) {
 			$col = $this->table->getColumn( $name );
@@ -511,7 +511,7 @@ public function hasForeign( $name ) : bool
 	 * @param string|null $name Name of the foreign key constraint and foreign key index or NULL for autogenerated name
 	 * @return \Aimeos\Upscheme\Schema\Foreign Foreign key constraint object
 	 */
-	public function foreign( $localcolumn, string $foreigntable, $foreigncolumn = 'id', string $name = null ) : Foreign
+	public function foreign( $localcolumn, string $foreigntable, $foreigncolumn = 'id', ?string $name = null ) : Foreign
 	{
 		$localcolumn = (array) $localcolumn;
 		$foreigncolumn = (array) $foreigncolumn;
@@ -549,7 +549,7 @@ public function foreign( $localcolumn, string $foreigntable, $foreigncolumn = 'i
 	 * @param array $options Associative key/value pairs of DB-specific index options
 	 * @return self Same object for fluid method calls
 	 */
-	public function index( $columns, string $name = null, array $flags = [], array $options = [] ) : self
+	public function index( $columns, ?string $name = null, array $flags = [], array $options = [] ) : self
 	{
 		$columns = (array) $columns;
 		$name = $name ?: $this->nameIndex( $this->name(), $columns, 'idx' );
@@ -624,7 +624,7 @@ public function opt( string $name, $value = null )
 	 * @param string|null $name Index name or NULL for autogenerated name
 	 * @return self Same object for fluid method calls
 	 */
-	public function primary( $columns, string $name = null ) : self
+	public function primary( $columns, ?string $name = null ) : self
 	{
 		$columns = (array) $columns;
 		$index = $this->table->getPrimaryKey();
@@ -654,7 +654,7 @@ public function primary( $columns, string $name = null ) : self
 	 * @param string|null $to New column name or NULL if first parameter is an array
 	 * @return self Same object for fluid method calls
 	 */
-	public function renameColumn( $from, string $to = null ) : self
+	public function renameColumn( $from, ?string $to = null ) : self
 	{
 		if( !$this->hasColumn( $from ) ) {
 			return $this;
@@ -672,7 +672,7 @@ public function renameColumn( $from, string $to = null ) : self
 	 * @param string|null $to New index name or NULL for autogenerated name (ignored if first parameter is an array)
 	 * @return self Same object for fluid method calls
 	 */
-	public function renameIndex( $from, string $to = null ) : self
+	public function renameIndex( $from, ?string $to = null ) : self
 	{
 		if( !is_array( $from ) ) {
 			$from = [$from => $to];
@@ -704,7 +704,7 @@ public function renameIndex( $from, string $to = null ) : self
 	 * @param string|null $name Index name or NULL for autogenerated name
 	 * @return self Same object for fluid method calls
 	 */
-	public function spatial( $columns, string $name = null ) : self
+	public function spatial( $columns, ?string $name = null ) : self
 	{
 		$columns = (array) $columns;
 		$name = $name ?: $this->nameIndex( $this->name(), $columns, 'idx' );
@@ -736,7 +736,7 @@ public function spatial( $columns, string $name = null ) : self
 	 * @param string|null $name Index name or NULL for autogenerated name
 	 * @return self Same object for fluid method calls
 	 */
-	public function unique( $columns, string $name = null ) : self
+	public function unique( $columns, ?string $name = null ) : self
 	{
 		$columns = (array) $columns;
 		$name = $name ?: $this->nameIndex( $this->name(), $columns, 'unq' );
diff --git a/src/Up.php b/src/Up.php
index 39d3407..352c4a4 100644
--- a/src/Up.php
+++ b/src/Up.php
@@ -311,11 +311,11 @@ protected function createTasks( array $paths ) : array
 	 */
 	protected function macros()
 	{
-		\Aimeos\Upscheme\Schema\Table::macro( 'id', function( string $name = null ) : Schema\Column {
+		\Aimeos\Upscheme\Schema\Table::macro( 'id', function( ?string $name = null ) : Schema\Column {
 			return $this->integer( $name ?: 'id' )->seq( true )->primary();
 		} );
 
-		\Aimeos\Upscheme\Schema\Table::macro( 'bigid', function( string $name = null ) : Schema\Column {
+		\Aimeos\Upscheme\Schema\Table::macro( 'bigid', function( ?string $name = null ) : Schema\Column {
 			return $this->bigint( $name ?: 'id' )->seq( true )->primary();
 		} );
 	}