TypeScript

MikroORM migrations, drawn as a database diagram

TypeScript migration classes extending Migration, with up() and down() running SQL. SchemaDrawer runs MikroORM 7.2 against a throw-away database of the engine you choose and returns an SVG of the schema it produces.

Get startedMikroORM documentation

What to upload

Upload the migration files directly, not in a nested folder: MikroORM does not look inside subdirectories, and an upload without a migration at the top level is refused. Each file exports a class extending Migration whose up() calls this.addSql(...).

The sample below is the PetClinic schema written for MikroORM, one of the sets SchemaDrawer's own tests draw on every engine:

migrations/
├── Migration20240101000001_create_owners_and_pets.ts
├── Migration20240101000002_create_vets.ts
└── Migration20240101000003_create_visits.ts

Formats

.ts, .js and .cjs files.

How it runs

mikro-orm migration:up with a generated configuration that declares no entities. The database is a fresh PostgreSQL, MySQL, MariaDB, SQL Server, Oracle or SQLite container in the version you ask for; nothing of yours is touched.

Databases you can draw MikroORM on

PostgreSQL 10, 11, 12, 13, 14, 15, 16, 17, 18 MySQL 8.0, 8.4, 9 MariaDB 10.6, 11.4, 11.8, 12 SQL Server 2017, 2019, 2022, 2025 Oracle SQLite

Not offered for MikroORM: Oracle, SQLite. The tool ships no driver for them, so nothing could run.

At a glance

Runs
MikroORM 7.2, run through its CLI
API value
migrationType=MIKRO_ORM
Engines
4 of 6: PostgreSQL, MySQL, MariaDB, SQL Server
Output
SVG diagram with tables, columns and types, primary and foreign keys
Price
Free today; enterprise plans are coming
Example

The PetClinic schema in MikroORM

Owners, pets, types, vets, specialties and visits: the same seven tables every sample set on this site creates. These are the exact files the tests upload.

import { Migration } from '@mikro-orm/migrations';

export class Migration20240101000001_create_owners_and_pets extends Migration {

  override name = 'Migration20240101000001_create_owners_and_pets';

  override up(): void | Promise<void> {
    this.addSql(`create table owners (
      id int not null,
      first_name varchar(50) not null,
      last_name varchar(50) not null,
      address varchar(255) null,
      city varchar(80) null,
      telephone varchar(20) null,
      constraint pk_owners primary key (id)
    )`);

    this.addSql(`create table types (
      id int not null,
      name varchar(80) not null,
      constraint pk_types primary key (id)
    )`);

    this.addSql(`create table pets (
      id int not null,
      name varchar(50) not null,
      birth_date date null,
      type_id int not null,
      owner_id int not null,
      constraint pk_pets primary key (id),
      constraint fk_pets_types foreign key (type_id) references types (id),
      constraint fk_pets_owners foreign key (owner_id) references owners (id)
    )`);
  }

  override down(): void | Promise<void> {
    this.addSql(`drop table pets`);
    this.addSql(`drop table types`);
    this.addSql(`drop table owners`);
  }

}

import { Migration } from '@mikro-orm/migrations';

export class Migration20240101000002_create_vets extends Migration {

  override name = 'Migration20240101000002_create_vets';

  override up(): void | Promise<void> {
    this.addSql(`create table vets (
      id int not null,
      first_name varchar(50) not null,
      last_name varchar(50) not null,
      constraint pk_vets primary key (id)
    )`);

    this.addSql(`create table specialties (
      id int not null,
      name varchar(80) not null,
      constraint pk_specialties primary key (id)
    )`);

    this.addSql(`create table vet_specialties (
      vet_id int not null,
      specialty_id int not null,
      constraint pk_vet_specialties primary key (vet_id, specialty_id),
      constraint fk_vet_specialties_vets foreign key (vet_id) references vets (id),
      constraint fk_vet_specialties_specialties foreign key (specialty_id) references specialties (id)
    )`);
  }

  override down(): void | Promise<void> {
    this.addSql(`drop table vet_specialties`);
    this.addSql(`drop table specialties`);
    this.addSql(`drop table vets`);
  }

}

import { Migration } from '@mikro-orm/migrations';

export class Migration20240101000003_create_visits extends Migration {

  override name = 'Migration20240101000003_create_visits';

  override up(): void | Promise<void> {
    this.addSql(`create table visits (
      id int not null,
      pet_id int not null,
      visit_date date null,
      description varchar(255) null,
      constraint pk_visits primary key (id),
      constraint fk_visits_pets foreign key (pet_id) references pets (id)
    )`);
  }

  override down(): void | Promise<void> {
    this.addSql(`drop table visits`);
  }

}
diagram.svg
ER diagram of the PetClinic schema drawn by SchemaDrawer: owners, pets, types, vets, specialties, vet_specialties and visits with their columns, primary keys and foreign keys

Every variant of the sample produces these seven tables. This diagram was drawn from the Flyway variant on PostgreSQL 18; on MySQL the types read INT and VARCHAR, on Oracle the names are upper case.

Run it

Draw your MikroORM migrations

One multipart request queues the drawing; poll the job until it succeeds and download the SVG. Or let the GitHub Action do it and open a pull request with the diagram.

With curl

curl -X POST https://schemadrawer.com/api/v1/drawing \
  -H "Request-Id: $(uuidgen)" \
  -F "userId=5f0c1d2e-3a4b-4c5d-8e6f-7a8b9c0d1e2f" \
  -F "migrationType=MIKRO_ORM" \
  -F "databaseType=POSTGRESQL" \
  -F "version=18" \
  -F "files=@migrations/Migration20240101000001_create_owners_and_pets.ts" \
  -F "files=@migrations/Migration20240101000002_create_vets.ts" \
  -F "files=@migrations/Migration20240101000003_create_visits.ts"
# {"jobId":"0b6e2f4c-8d1a-4c3e-9f7a-2a5b6c7d8e9f"}

Then poll GET https://schemadrawer.com/api/v1/drawing/{jobId} until status is SUCCESS and fetch diagramUrl. Details in the getting started guide and the API reference.

With the GitHub Action

- uses: schemadrawercom/action@v1
  with:
    sql-directory: migrations
    output-path: docs/schema-diagram.svg
    migration-type: MIKRO_ORM
    database-type: POSTGRESQL
    database-version: '18'
    github-token: ${{ secrets.GITHUB_TOKEN }}

The action uploads the directory, waits for the diagram and opens a pull request with the SVG. See the action reference.

Good to know

  • The SQL inside addSql runs verbatim, so it has to be valid for the engine you draw on.
  • The mikro_orm_migrations table is left out of the diagram.
  • A drawing may take up to 120 seconds; a job that waits in the queue longer than 10 minutes fails rather than draws. Uploads of up to 100 MB and 2000 files are accepted.
From the blog

Reading about MikroORM and migrations

Draw your MikroORM schema now

Upload the migration directory, get an SVG back. Free while we build it.

Get started See examples