Validates Postgres foreign key ON DELETE and ON UPDATE actions.

Examples

With this rule:

[only: [referenced_table: "accounts"], on_delete: :restrict]

Before, the foreign key deletes orders when an account is deleted:

CREATE TABLE orders (
  id uuid PRIMARY KEY,
  account_id uuid NOT NULL REFERENCES accounts(id) ON DELETE CASCADE
);

That may silently remove business records that should survive account cleanup or require an explicit archival flow.

After, use the action required by the rule:

CREATE TABLE orders (
  id uuid PRIMARY KEY,
  account_id uuid NOT NULL REFERENCES accounts(id) ON DELETE RESTRICT
);

Postgres now blocks accidental parent deletion until the application handles dependent rows intentionally.

Notes

This check only validates actions you configure. If a rule only sets on_delete, the ON UPDATE action is ignored for that rule.

Options

Use a rule without :only when every foreign key in scope should use the same action:

{Bylaw.Db.Adapters.Postgres.Checks.ForeignKeyActions,
 rules: [[on_delete: :cascade]]}

Use rules: [...] for scoped policy. A foreign key can match more than one rule, and matching rules accumulate.

{Bylaw.Db.Adapters.Postgres.Checks.ForeignKeyActions,
 rules: [
   [
     only: [[table: "messages"], [referenced_table: "conversations"]],
     on_delete: :cascade
   ],
   [
     only: [referenced_table: "lookup_statuses"],
     on_delete: :restrict,
     on_update: :restrict
   ]
 ]}

Usage

Add this module to the checks passed to Bylaw.Db.Adapters.Postgres.validate/2. See the README usage section for the full ExUnit setup.