Check constraints

Check constraints are defined in the constraints object of table definition using the check function.

import { integer, table, check } from "@monolayer/pg/schema";
import { sql } from "kysely";

export const books = table({
  columns: {
    id: integer(),
    price: integer(),
  },
  constraints: {
    check: check(sql`${sql.ref("price")} > 0`), 
  },
});

A check constraint can refer also to multiple columns:

import { integer, table, check } from "@monolayer/pg/schema";
import { sql } from "kysely";

export const books = table({
  columns: {
    id: integer(),
    price: integer(),
    discount: integer(),
  },
  constraints: {
    check: check(  
      sql`${sql.ref("price")} > 0 AND ${sql.ref("discount")} >= 10`
    ), 
  },
});

DANGER

It's recommended to reference column names with the sql.ref function. This function takes care of:

• Double quote the column name (PostgreSQL lower cases all names unless they are "double quoted" ).
• Transform to the column name to snake_case when the camelCase option is active.