add snowflake adapter

lib/odbc_adapter/adapters/snowflake_odbc_adapter.rb

@@ -0,0 +1,50 @@
+require 'odbc_adapter/adapters/postgresql_odbc_adapter'
+
+module ODBCAdapter
+  module Adapters
+    # Overrides specific to Snowflake. Mostly taken from
+    # https://eng.localytics.com/connecting-to-snowflake-with-ruby-on-rails/
+    class SnowflakeODBCAdapter < PostgreSQLODBCAdapter
+      # Explicitly turning off prepared statements as they are not yet working with
+      # snowflake + the ODBC ActiveRecord adapter
+      def prepared_statements
+        false
+      end
+
+      # Quoting needs to be changed for snowflake
+      def quote_column_name(name)
+        name.to_s
+      end
+
+      private
+
+      # Override dbms_type_cast to get the values encoded in UTF-8
+      def dbms_type_cast(columns, values)
+        int_column = {}
+        columns.each_with_index do |c, i|
+          int_column[i] = c.type == 3 && c.scale.zero?
+        end
+
+        float_column = {}
+        columns.each_with_index do |c, i|
+          float_column[i] = c.type == 3 && !c.scale.zero?
+        end
+
+        values.each do |row|
+          row.each_index do |idx|
+            val = row[idx]
+            if val
+              if int_column[idx]
+                row[idx] = val.to_i
+              elsif float_column[idx]
+                row[idx] = val.to_f
+              elsif val.is_a?(String)
+                row[idx] = val.force_encoding('UTF-8')
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/odbc_adapter/registry.rb

@@ -5,7 +5,8 @@ class Registry
     def initialize
       @dbs = {
         /my.*sql/i  => :MySQL,
-        /postgres/i => :PostgreSQL
+        /postgres/i => :PostgreSQL,
+        /snowflake/i => :Snowflake
       }
     end