1 files changed, 30 insertions, 0 deletions
diff --git a/db/migrate/20170622132212_add_foreign_key_for_merge_request_diffs.rb b/db/migrate/20170622132212_add_foreign_key_for_merge_request_diffs.rb
new file mode 100644
index 00000000000..9f524fac8a7
--- /dev/null
+++ b/db/migrate/20170622132212_add_foreign_key_for_merge_request_diffs.rb
@@ -0,0 +1,30 @@
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddForeignKeyForMergeRequestDiffs < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    execute <<-EOF
+    DELETE FROM merge_request_diffs
+    WHERE NOT EXISTS (
+      SELECT true
+      FROM merge_requests
+      WHERE merge_requests.id = merge_request_diffs.merge_request_id
+    )
+    EOF
+
+    add_concurrent_foreign_key(:merge_request_diffs,
+                               :merge_requests,
+                               column: :merge_request_id)
+  end
+
+  def down
+    remove_foreign_key(:merge_request_diffs, column: :merge_request_id)
+  end
+end