This release includes a feature I added [1] to support partial foreign key updates in referential integrity triggers! This is useful for schemas that use a den

This release includes a feature I added [1] to support partial foreign key updates in referential integrity triggers! This is useful for schemas that use a denormalized tenant id across multiple tables, as might be common in a multi-tenant application: CREATE TABLE tenants (id serial PRIMARY KEY); CREATE TABLE users ( tenant_id int REFERENCES tenants ON DELETE CASCADE, id serial, PRIMARY KEY (tenant_id, id), ); CREATE TABLE posts ( tenant_id int REFERENCES tenants ON DELETE CASCADE, id serial, author_id int, PRIMARY KEY (tenant_id, id), FOREIGN KEY (tenant_id, author_id) REFERENCES users ON DELETE SET NULL ); This schema has a problem. When you delete a user, it will try to set both the tenant_id and author_id columns on the posts table to NULL: INSERT INTO tenants VALUES (1); INSERT INTO users VALUES (1, 101); INSERT INTO posts VALUES (1, 201, 101); DELETE FROM users WHERE id = 101; ERROR: null value in column "tenant_id" violates not-null constraint DETAIL: Failing row contains (null, 201, null). When we delete a user, we really only want to clear the author_id column in the posts table, and we want to leave the tenant_id column untouched. The feature I added is a small syntax extension to support doing exactly this. You can provide an explicit column list to the ON DELETE SET NULL / ON DELETE SET DEFAULT actions: CREATE TABLE posts ( tenant_id int REFERENCES tenants ON DELETE CASCADE, id serial, author_id int, PRIMARY KEY (tenant_id, id), FOREIGN KEY (tenant_id, author_id) -- Clear only author_id, not tenant_id REFERENCES users ON DELETE SET NULL (author_id) -- ^^^^^^^^^^^ ); I initially encountered this problem while converting a database to use composite primary keys in preparation for migrating to Citus [2], and it required adding custom triggers for every single foreign key we created. Now it can be handled entirely by Postgres! [1]: https://www.postgresql.org/message-id/flat/CACqFVBZQyMYJV%3DnjbSMxf%2BrbDHpx%3DW%3DB7AEaMKn8dWn9OZJY7w%40mail.gmail.com https://www.postgresql.org/message-id/flat/CACqFVBZQyMYJV%3D... [2]: https://www.citusdata.com/ https://www.citusdata.com/