3 files changed, 88 insertions, 0 deletions
diff --git a/gems/gitlab-schema-validation/lib/gitlab/schema/validation/sources/connection_adapters/active_record_adapter.rb b/gems/gitlab-schema-validation/lib/gitlab/schema/validation/sources/connection_adapters/active_record_adapter.rb
new file mode 100644
index 00000000000..10af0fc3647
--- /dev/null
+++ b/gems/gitlab-schema-validation/lib/gitlab/schema/validation/sources/connection_adapters/active_record_adapter.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Schema
+    module Validation
+      module Sources
+        module ConnectionAdapters
+          class ActiveRecordAdapter < Base
+            extend Forwardable
+
+            def_delegators :@connection, :current_schema
+
+            def exec_query(sql, schemas)
+              connection.exec_query(sql, nil, schemas)
+            end
+
+            def select_rows(sql, schemas)
+              connection.select_rows(sql, nil, schemas)
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/gems/gitlab-schema-validation/lib/gitlab/schema/validation/sources/connection_adapters/base.rb b/gems/gitlab-schema-validation/lib/gitlab/schema/validation/sources/connection_adapters/base.rb
new file mode 100644
index 00000000000..713cbbe0a6d
--- /dev/null
+++ b/gems/gitlab-schema-validation/lib/gitlab/schema/validation/sources/connection_adapters/base.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Schema
+    module Validation
+      module Sources
+        module ConnectionAdapters
+          class Base
+            def initialize(connection)
+              @connection = connection
+            end
+
+            def current_schema
+              raise NotImplementedError, "#{self.class} does not implement #{__method__}"
+            end
+
+            def select_rows(sql, schemas = [])
+              raise NotImplementedError, "#{self.class} does not implement #{__method__}"
+            end
+
+            def exec_query(sql, schemas = [])
+              raise NotImplementedError, "#{self.class} does not implement #{__method__}"
+            end
+
+            private
+
+            attr_reader :connection
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/gems/gitlab-schema-validation/lib/gitlab/schema/validation/sources/connection_adapters/pg_adapter.rb b/gems/gitlab-schema-validation/lib/gitlab/schema/validation/sources/connection_adapters/pg_adapter.rb
new file mode 100644
index 00000000000..4dcaf15be71
--- /dev/null
+++ b/gems/gitlab-schema-validation/lib/gitlab/schema/validation/sources/connection_adapters/pg_adapter.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Schema
+    module Validation
+      module Sources
+        module ConnectionAdapters
+          class PgAdapter < Base
+            def initialize(connection)
+              @connection = connection
+              @connection.type_map_for_results = PG::BasicTypeMapForResults.new(connection)
+            end
+
+            def current_schema
+              connection.exec('SELECT current_schema').first['current_schema']
+            end
+
+            def exec_query(sql, schemas)
+              connection.exec(sql, schemas)
+            end
+
+            def select_rows(sql, schemas)
+              exec_query(sql, schemas).values
+            end
+          end
+        end
+      end
+    end
+  end
+end