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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
提示
  • 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
备注
// 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();
}

STI

  • STI -> Single Table Inheritance 单表继承
@Entity({
discriminatorColumn: 'type',
// discriminatorMap: { person: 'Person', employee: 'Employee' },
// discriminatorValue: 'person',
abstract: true, // discriminatorMap 不包含自己
})
export class BasePerson {
@Enum()
type!: 'person' | 'employee';
}
@Entity({
discriminatorValue: 'person',
})
export class Person extends BasePerson {
// ...
}
@Entity({
discriminatorValue: 'employee',
})
export class Employee extends BasePerson {}

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

Metadata

  • MetadataStorage
    • Key ->EntityMetadata
    • key = entity && path ? entity + '-' + Utils.hash(path) : null
  • Utils.lookupPathFromDecorator
    • 获取 Decorator 调用的 path
// true
DemoEntity.prototype.__entity;
// boolean
DemoEntity.prototype.__baseEntity;
// EntityMetadata
DemoEntity.prototype.__meta;
DemoEntity.prototype.__config;
DemoEntity.prototype.__platform;
DemoEntity.prototype.__factory;
DemoEntity.prototype.__helper;
MetadataStorage.getMetadataFromDecorator(UserEntity);

@Entity

export function Entity(options: EntityOptions<any> = {}) {
return function <T>(target: T & Dictionary) {
const meta = MetadataStorage.getMetadataFromDecorator(target);
Utils.mergeConfig(meta, options);
meta.class = target as unknown as Constructor<T>;

if (!options.abstract || meta.discriminatorColumn) {
meta.name = target.name;
}

return target;
};
}

EntitySchema

可以动态增加

const schema = new EntitySchema({
tableName: 'myNewTable',
name: 'myNewTable',
properties: {
id: { primary: true, type: 'string' },
price: { type: 'number', nullable: true, columnType: 'float' },
},
});
orm.discoverEntity(schema);
em.create('myNewTable', { id: 'abc-123', price: 1.5 });
await em.flush();

Migration

pnpm add -D @mikro-orm/cli
npx mikro-orm migration:create --initial

pnpm --package=@mikro-orm/cli dlx mikro-orm migration:create --initial