postgresql/require-index-on-fk-column

Why this matters

An unindexed foreign-key column makes parent-side `DELETE` / `UPDATE` perform a sequential scan of the child table to enforce the constraint. The check is cross-statement: it scans `CREATE TABLE`, `CREATE INDEX`, and `ALTER TABLE ADD CONSTRAINT` in the same file, and only requires an index whose leading column is the FK column. The PRIMARY KEY index already counts.

Examples

CREATE TABLE t (
  id integer PRIMARY KEY,
  fid integer REFERENCES other(id)
);
-- No CREATE INDEX on t.fid in this file.

CREATE TABLE t (
  id integer PRIMARY KEY,
  fid integer REFERENCES other(id)
);
CREATE INDEX idx_t_fid ON t (fid);

Configure it

// eslint.config.js
import postgresql from "eslint-plugin-postgresql";

export default [
  {
    files: ["**/*.sql"],
    languageOptions: {
      parser: postgresql.configs.recommended.languageOptions.parser,
    },
    plugins: { postgresql },
    rules: {
      "postgresql/require-index-on-fk-column": "warn",
    },
  },
];

Options

This rule has no options.