CodeIsTheEnd

    [alias]
        lg = log --graph --abbrev-commit --decorate --date=relative --format=format:'%C(bold blue)%h%C(reset) - %C(bold green)(%ar)%C(reset) %C(white)%s%C(reset) %C(dim white)- %an%C(reset)%C(bold yellow)%d%C(reset)' --all -n 15

    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
    );

    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).

    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)
          --                                  ^^^^^^^^^^^
    );