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mikro-orm

  • mikro-orm/mikro-orm
    • MIT, Typescript
    • ORM
    • 支持 Data Mapper, Unit of Work, Identity Map
    • 支持 MongoDB, MySQL, MariaDB, PostgreSQL, SQLite
    • 支持 dataloader
  • @mikro-orm/knex
    • Builder
tip
  • mikro-orm 使用 knex， knex pool 默认 min:2, max:10
  • 不支持复杂多样的 JOIN 逻辑
  • 默认 cascade 为 persist
    • 新 entity 总会 persist - 忽略 cascade
note
// 让 user 和 userId 同时存在
@Property({ persist: false })
get userId(): string {
  return this.user.id;
}
const filters = em.applyFilters('EntityName', {}, {}, 'read');
qb.andWhere(filters);
# mongodb, mysql, mariadb, sqlite
npm add @mikro-orm/core @mikro-orm/postgresql
tsconfig.json
{
  "experimentalDecorators": true,
  "emitDecoratorMetadata": true,
  "esModuleInterop": true
}
import type { PostgreSqlDriver } from '@mikro-orm/postgresql'; // or any other driver package
import { EntityManager } from '@mikro-orm/postgresql';

const orm = await MikroORM.init<PostgreSqlDriver>({
  // 自动发现 - 不推荐
  // entities: ['./dist/entities'], // path to our JS entities (dist), relative to `baseDir`
  // entitiesTs: ['./src/entities'], // path to our TS entities (src), relative to `baseDir`
  // entities: ['./dist/app/**/entities'],
  // entitiesTs: ['./src/app/**/entities'],
  // entities: ['./dist/app/**/entities/*.entity.js'],
  // entitiesTs: ['./src/app/**/entities/*.entity.ts'],

  // 手动配置
  entities: [Author, Book, BookTag, Publisher, Test],
  discovery: { disableDynamicFileAccess: true },

  dbName: 'my-db-name',
  type: 'postgresql',
});
const em = orm.em as EntityManager;
npm add -D @mikro-orm/cli
# mikro-orm.config.js
npx mikro-orm

mikro-orm generate-entities

# by dlx
pnpm --package=@mikro-orm/cli dlx mikro-orm

NODE_OPTIONS='--loader tsx' pnpm mikro-orm generate-entities --schema public -p ./src/server/db/entities/ -d
  • mikro-orm.config.ts
    • 依赖 ts-node
export type MinimalOptionalEntityFields =
  | 'id'
  | 'uid'
  | 'createdAt'
  | 'updatedAt'
  | 'sid'
  | 'tid'
  | 'attributes'
  | 'properties'
  | 'extensions';

@Entity({ abstract: true })
export abstract class MinimalBaseEntity<Entity extends MinimalBaseEntity<any>> extends BaseEntity<Entity, 'id'> {
  // 在子类中定义 - Base 里的定义无法覆盖
  [OptionalProps]?: MinimalOptionalEntityFields;

  @PrimaryKey({ type: 'text', defaultRaw: 'public.gen_ulid()' })
  id!: string;

  //@PrimaryKey({ type: 'uuid', defaultRaw: 'uuid_generate_v4()' })
  @PrimaryKey({ type: 'uuid', defaultRaw: 'gen_random_uuid()' })
  uid!: string;

  @Property()
  createdAt: Date = new Date();

  @Property({ type: 'timestamptz', defaultRaw: 'current_timestamp' })
  createdAt!: Date;

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

Collection​

interface Collection<T> {
  load(): Promise<this>;
  loadItems(): Promise<T[]>;
  loadCount(): Promise<number>;

  matching(cond: FilterQuery<T>): this;

  getItems(): T[];

  add(...items: T[]): this;
  remove(...items: T[]): this;
  contains(item: T): boolean;
  count(): number;

  // 数组
  slice(start?: number, end?: number): T[];
  exists(cb: (item: T) => boolean): boolean;
  find(cb: (item: T, index: number) => boolean): T | undefined;
  filter(cb: (item: T, index: number) => boolean): T[];
  map<R>(mapper: (item: T, index: number) => R): R[];
  indexBy<K extends keyof T>(prop: K): Record<string, T>;

  shouldPopulate(populated?: boolean): boolean;
  populated(populated?: boolean): boolean;
  init(): Promise<this>;

  toJSON(): any;
}

RequestContext​

  • Middleware RequestContext.create(orm.em, next)

Relationships​

Version

MikroORM v6​

  • 类型
    • populate 类型安全
    • Opt 类型 - 解决之前需要 OptionalProps 的问题，不好扩展
    • Hidden 类型 - 序列化后字段不存在
    • BaseEntity 不再需要类型参数，通过 PrimaryKeyProp 定义
    • [Config]?: DefineConfig<{ forceObject: true }>;
      • 序列化后类型为 object
  • 查询
    • populate 支持 * - 所有，之前的 true
    • populate 支持 $infer - 基于查询
    • Collection 接口功能完善 - 类似 数组
    • findByCursor - 基于游标分页
    • 关联子查询 some,some, none, $every
  • helper
    • rel
    • ref
  • dataloader
  • Logging
    • 支持 label、context
    • 可以按需关闭
  • 可以扩展 EntityManager
  • 解决默认 require 插件依赖问题
  • MikroORM.initSync
  • 元数据生成 adapter
    • GeneratedCacheAdapter
    • npx mikro-orm cache:generate --combined
    • 可以避免 reflect-metadata 、 @mikro-orm/reflection
MikroORM.init({
  metadataCache: {
    enabled: true,
    adapter: GeneratedCacheAdapter,
    options: { data: require('./temp/metadata.json') },
  },
});

//
MikroORM.init({
  dataloader: Dataloader.ALL,
});

FAQ

LockMode​

OPTIMISTIC
PESSIMISTIC_READ
PESSIMISTIC_WRITE
PESSIMISTIC_PARTIAL_WRITE
PESSIMISTIC_WRITE_OR_FAIL
PESSIMISTIC_PARTIAL_READ
  • PESSIMISTIC_WRITE_OR_FAIL
    • FOR UPDATE NOWAIT

Transaction query already complete​