PostgreSQL Migration: Issues with Foreign Key Constraints and Circular References
I'm upgrading from an older version and I'm collaborating on a project where This might be a silly question, but I've been banging my head against this for hours....... During a migration from an older version of PostgreSQL to 14, I've encountered some unexpected behavior when it comes to foreign key constraints. The existing schema has a couple of tables, `orders` and `payments`, that reference each other in a circular manner. The `orders` table has a foreign key to `payments`, and the `payments` table has a foreign key to `orders`. While this was working fine in the previous version, now I'm getting an error about foreign key violations when trying to insert records into either table. Here's a simplified version of the table definitions: ```sql CREATE TABLE orders ( order_id SERIAL PRIMARY KEY, payment_id INT, CONSTRAINT fk_payment FOREIGN KEY (payment_id) REFERENCES payments(payment_id) ); CREATE TABLE payments ( payment_id SERIAL PRIMARY KEY, order_id INT, CONSTRAINT fk_order FOREIGN KEY (order_id) REFERENCES orders(order_id) ); ``` Initial attempts to insert data into these tables resulted in: ``` ERROR: insert or update on table "orders" violates foreign key constraint "fk_payment" DETAIL: Key (payment_id)=(1) is not present in table "payments". ``` What I’ve tried so far is to disable the foreign keys temporarily and then re-enable them after populating the tables: ```sql ALTER TABLE orders DROP CONSTRAINT fk_payment; ALTER TABLE payments DROP CONSTRAINT fk_order; -- Insert logic here ALTER TABLE orders ADD CONSTRAINT fk_payment FOREIGN KEY (payment_id) REFERENCES payments(payment_id); ALTER TABLE payments ADD CONSTRAINT fk_order FOREIGN KEY (order_id) REFERENCES orders(order_id); ``` This approach seems to work, but it feels like I’m circumventing the issue rather than truly resolving it. Is there a more elegant way to handle this during the migration? I'm also concerned about the integrity of the data while using this method. Any insights into managing circular references effectively in PostgreSQL would be greatly appreciated. For context: I'm using Sql on macOS. What am I doing wrong? My development environment is macOS. Is there a better approach? I'm working with Sql in a Docker container on Ubuntu 20.04. I'm working in a Windows 10 environment. Any feedback is welcome!