Drizzle ORM - Empty array as a default value

Drizzle | Empty array as a default value

This guide assumes familiarity with:

Get started with PostgreSQL, MySQL and SQLite
Learn about column data types for PostgreSQL, MySQL and SQLite
sql operator

PostgreSQL

To set an empty array as a default value in PostgreSQL, you can use sql operator with '{}' or ARRAY[] syntax:

import { sql } from 'drizzle-orm';
import { pgTable, serial, text } from 'drizzle-orm/pg-core';

export const users = pgTable('users', {
  id: serial('id').primaryKey(),
  name: text('name').notNull(),
  tags1: text('tags1')
    .array()
    .notNull()
    .default(sql`'{}'::text[]`),
  tags2: text('tags2')
    .array()
    .notNull()
    .default(sql`ARRAY[]::text[]`),
});

CREATE TABLE IF NOT EXISTS "users" (
  "id" serial PRIMARY KEY NOT NULL,
  "name" text NOT NULL,
  "tags1" text[] DEFAULT '{}'::text[] NOT NULL,
  "tags2" text[] DEFAULT ARRAY[]::text[] NOT NULL
);

MySQL

MySQL doesn’t have an array data type, but you can use json data type for the same purpose. To set an empty array as a default value in MySQL, you can use JSON_ARRAY() function or sql operator with ('[]') syntax:

import { sql } from 'drizzle-orm';
import { json, mysqlTable, serial, varchar } from 'drizzle-orm/mysql-core';

export const users = mysqlTable('users', {
  id: serial('id').primaryKey(),
  name: varchar('name', { length: 255 }).notNull(),
  tags1: json('tags1').$type<string[]>().notNull().default([]),
  tags2: json('tags2')
    .$type<string[]>()
    .notNull()
    .default(sql`('[]')`), // the same as default([])
  tags3: json('tags3')
    .$type<string[]>()
    .notNull()
    .default(sql`(JSON_ARRAY())`),
});

CREATE TABLE `users` (
  `id` serial AUTO_INCREMENT NOT NULL,
  `name` varchar(255) NOT NULL,
  `tags1` json NOT NULL DEFAULT ('[]'),
  `tags2` json NOT NULL DEFAULT ('[]'),
  `tags3` json NOT NULL DEFAULT (JSON_ARRAY()),
  CONSTRAINT `users_id` PRIMARY KEY(`id`)
);

The mode option defines how values are handled in the application. With json mode, values are treated as JSON object literal.

You can specify .$type<..>() for json object inference, it will not check runtime values. It provides compile time protection for default values, insert and select schemas.

SQLite

SQLite doesn’t have an array data type, but you can use text data type for the same purpose. To set an empty array as a default value in SQLite, you can use json_array() function or sql operator with '[]' syntax:

import { sql } from 'drizzle-orm';
import { integer, sqliteTable, text } from 'drizzle-orm/sqlite-core';

export const users = sqliteTable('users', {
  id: integer('id').primaryKey(),
  tags1: text('tags1', { mode: 'json' })
    .notNull()
    .$type<string[]>()
    .default(sql`(json_array())`),
  tags2: text('tags2', { mode: 'json' })
    .notNull()
    .$type<string[]>()
    .default(sql`'[]'`),
});

CREATE TABLE `users` (
  `id` integer PRIMARY KEY NOT NULL,
  `tags1` text DEFAULT (json_array()) NOT NULL,
  `tags2` text DEFAULT '[]' NOT NULL
);

The mode option defines how values are handled in the application. With json mode, values are treated as JSON object literal.

You can specify .$type<..>() for json object inference, it will not check runtime values. It provides compile time protection for default values, insert and select schemas.

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