Instruction file imported from BetterTyped/hype-stack (.cursor/rules/backend-deletion-cascades.mdc). Copyright stays with the author.

Backend Deletion Cascades

When removing a backend domain entity, delete all of its owned dependencies as part of the same mutation.

• Perform dependent deletes in a single database transaction.
• Keep delete logic in the relevant db/mutations function.
• Delete child records before the parent record when database constraints require it.
• Do not leave placeholder delete mutations that only return the removed entity ID.

Example:

import { postgres } from "@backend/context";

export const deleteProjectMutation = async ({
  projectId,
}: {
  projectId: string;
}) => {
  await postgres.qb.transaction().execute(async (trx) => {
    await trx
      .deleteFrom("document")
      .where("projectId", "=", projectId)
      .execute();
    await trx.deleteFrom("project").where("id", "=", projectId).execute();
  });

  return { projectId };
};