MikroORM Entity Guide

Use this skill when creating or modifying MikroORM entity files (*.entity.ts ).

Basic Entity Structure

import { Entity, PrimaryKey, Property, Unique } from '@mikro-orm/core'; import { uuidv7 } from 'uuidv7';

import { EntityEnum } from '../entity.enums';

@Entity() export class EntityName { @PrimaryKey({ type: 'uuid' }) id: string = uuidv7();

@Property() @Unique() uniqueField!: string;

@Property({ length: 30, nullable: true }) optionalField?: string;

@Property({ type: 'date', nullable: true }) dateField?: Date;

@Property({ type: 'string', nullable: true }) enumField?: EntityEnum;

@Property({ onCreate: () => new Date() }) createdAt?: Date;

@Property({ onCreate: () => new Date(), onUpdate: () => new Date() }) updatedAt?: Date; }

Core Rules

1. Primary Key

• Use UUID v7: Use uuidv7 package for time-ordered UUIDs

• Assign default value directly in class field (= uuidv7() )

2. Property Decorators

• Required fields: Use ! (definite assignment assertion)

• Optional fields: Use ? (optional) with nullable: true option

• String length limits: Use length option

• Date type: Explicitly specify { type: 'date' }

3. Enum Fields

• Use @Property({ type: 'string' })

• Define enums in separate .enums.ts file

4. Timestamps

• onCreate : Auto-set on creation

• onUpdate : Auto-update on modification

• Both fields declared as optional (? )

5. Unique Constraints

• Place @Unique() decorator below @Property()

Enum File Structure (*.enums.ts)

export enum EntityStatus { ACTIVE = 'ACTIVE', INACTIVE = 'INACTIVE', DELETED = 'DELETED', }

export enum EntityType { TYPE_A = 'TYPE_A', TYPE_B = 'TYPE_B', }

• Values in uppercase SNAKE_CASE

• Keep key and value identical

File Naming Conventions

• Entity file: {entity-name}.entity.ts

• Enum file: {module-name}.enums.ts

• Folder structure: src/{module}/entities/