1 files changed, 32 insertions, 0 deletions
diff --git a/rubocop/cop/database/multiple_databases.rb b/rubocop/cop/database/multiple_databases.rb
new file mode 100644
index 00000000000..fb6e81f9845
--- /dev/null
+++ b/rubocop/cop/database/multiple_databases.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Database
+      # @example
+      #   # bad
+      #   ActiveRecord::Base.connection
+      #
+      #   # good
+      #   ApplicationRecord.connection
+      #
+      class MultipleDatabases < RuboCop::Cop::Cop
+        AR_BASE_MESSAGE = <<~EOF
+          Do not use methods from ActiveRecord::Base, use the ApplicationRecord class instead
+          For fixing offenses related to the ActiveRecord::Base.transaction method, see our guidelines:
+          https://docs.gitlab.com/ee/development/database/transaction_guidelines.html
+        EOF
+
+        def_node_matcher :active_record_base_method_is_used?, <<~PATTERN
+        (send (const (const nil? :ActiveRecord) :Base) $_)
+        PATTERN
+
+        def on_send(node)
+          return unless active_record_base_method_is_used?(node)
+
+          add_offense(node, location: :expression, message: AR_BASE_MESSAGE)
+        end
+      end
+    end
+  end
+end