banCreateDomainWithConstraint¶

Group safety · Migrations only · Since Unreleased
Diagnostic lint/banCreateDomainWithConstraint

Sources: inspired by squawk/ban-create-domain-with-constraint

Description¶

Domains with constraints have poor support for online migrations.

Any later change to the constraint of a domain revalidates every column that uses the domain, and coercing a column to a domain with constraints rewrites the table. Postgres can't reason about arbitrary domain constraints the way it can about simple column types.

Put the constraint on the columns directly instead.

Examples¶

Invalid¶

create domain positive_int as int check (value > 0);

code-block.sql:1:1 lint/banCreateDomainWithConstraint ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Domains with constraints have poor support for online migrations.

  > 1 │ create domain positive_int as int check (value > 0);
      │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    2 │ 

  i Changing the constraint later revalidates every column that uses the domain.

  i Use table and column constraints instead.

Valid¶

create domain name_text as text collate "C";

How to configure¶

{
  "linter": {
    "rules": {
      "banCreateDomainWithConstraint": "error"
    }
  }
}

How to suppress¶

Suppress this diagnostic with a comment:

-- pgls-ignore banCreateDomainWithConstraint