주니어개발자 앱개발기3 - TypeORM Relations, migration errors

하루 종일 삽질한 끝에 TypeORM에 대해 좀 명확하게 이해하게 된 것 같다.

이제 TypeORM CLI로 마이그레이션 할 수 있다!

 

뿌듯! typeORM cli 마이그레이션으로 생성한 users 테이블!!!

하루 종일 공부하고 삽질해서 얻은 테이블이라 더 기쁘다.

 

할 것

• TypeORM으로 users 테이블 migration하기
• AWS EC2, RDS 보안설정
• RDS에 API검색용 DB구축
• EC2에 코드 올리기

 

---

공부 한 것

1. TypeORM-Relations

https://typeorm.io/#/relations

relation: typeORM에서 테이블 간의 조인 관계를 나타냄

• one-to-one using @OneToOne
• many-to-one using @ManyToOne
• one-to-many using @OneToMany
• many-to-many using @ManyToMany

 

1-1. Relation options

• eager: boolean - If set to true, the relation will always be loaded with the main entity when using find* methods or QueryBuilder on this entity
• cascade: boolean | ("insert" | "update" | "remove")[] - If set to true, the related object will be inserted and updated in the database. You can also specify an array of cascade options.
• onDelete: "RESTRICT"|"CASCADE"|"SET NULL" - specifies how foreign key should behave when referenced object is deleted
• primary: boolean - Indicates whether this relation's column will be a primary column or not.
• nullable: boolean - Indicates whether this relation's column is nullable or not. By default it is nullable.

 

1-2. Cascade

import {Entity, PrimaryGeneratedColumn, Column, ManyToMany} from "typeorm";
import {Question} from "./Question";

@Entity()
export class Category {

    @PrimaryGeneratedColumn()
    id: number;

    @Column()
    name: string;

    @ManyToMany(type => Question, question => question.categories)
    questions: Question[];

}

 

import {Entity, PrimaryGeneratedColumn, Column, ManyToMany, JoinTable} from "typeorm";
import {Category} from "./Category";

@Entity()
export class Question {

    @PrimaryGeneratedColumn()
    id: number;

    @Column()
    title: string;

    @Column()
    text: string;

    @ManyToMany(type => Category, category => category.questions, {
        cascade: true
    })
    @JoinTable()
    categories: Category[];

}

 

const category1 = new Category();
category1.name = "animals";

const category2 = new Category();
category2.name = "zoo";

const question = new Question();
question.categories = [category1, category2];
await connection.manager.save(question);

 

1-3. Cascade Options

cascade옵션은 boolean값이나 cascade 옵션("insert", "update", "remove")을 배열로 넣으면 된다.

relation에서 cascade의 기본 값은 false이다.

@Entity(Post)
export class Post {

    @PrimaryGeneratedColumn()
    id: number;

    @Column()
    title: string;

    @Column()
    text: string;

    // Full cascades on categories.
    @ManyToMany(type => PostCategory, {
        cascade: true
    })
    @JoinTable()
    categories: PostCategory[];

    // Cascade insert here means if there is a new PostDetails instance set
    // on this relation, it will be inserted automatically to the db when you save this Post entity
    @ManyToMany(type => PostDetails, details => details.posts, {
        cascade: ["insert"]
    })
    @JoinTable()
    details: PostDetails[];

    // Cascade update here means if there are changes to an existing PostImage, it
    // will be updated automatically to the db when you save this Post entity
    @ManyToMany(type => PostImage, image => image.posts, {
        cascade: ["update"]
    })
    @JoinTable()
    images: PostImage[];

    // Cascade insert & update here means if there are new PostInformation instances
    // or an update to an existing one, they will be automatically inserted or updated
    // when you save this Post entity
    @ManyToMany(type => PostInformation, information => information.posts, {
        cascade: ["insert", "update"]
    })
    @JoinTable()
    informations: PostInformation[];
}

 

1-4. JoinColumn Options

@JoinColumn not only defines which side of the relation contains the join column with a foreign key, but also allows you to customize join column name and referenced column name.

When we set @JoinColumn, it automatically creates a column in the database named propertyName + referencedColumnName.

@ManyToOne(type => Category)
@JoinColumn() // this decorator is optional for @ManyToOne, but required for @OneToOne
category: Category;

This code will create a categoryId column in the database. If you want to change this name in the database you can specify a custom join column name:

@ManyToOne(type => Category)
@JoinColumn({ name: "cat_id" })
category: Category;

 

1-5. JoinTable Options

@JoinTable is used for many-to-many relations and describes join columns of the "junction" table. A junction table is a special separate table created automatically by TypeORM with columns that refer to the related entities. You can change column names inside junction tables and their referenced columns with @JoinColumn: You can also change the name of the generated "junction" table.

@ManyToMany(type => Category)
@JoinTable({
    name: "question_categories", // table name for the junction table of this relation
    joinColumn: {
        name: "question",
        referencedColumnName: "id"
    },
    inverseJoinColumn: {
        name: "category",
        referencedColumnName: "id"
    }
})
categories: Category[];

If the destination table has composite primary keys, then an array of properties must be sent to @JoinTable.

 

---

2. TypeORM migration errors

2-1. migration error 1

typeORM cli로 마이그레이션을 하려고 했더니 자꾸 위와 같은 에러가 발생해서 골머리를 앓다가 아래 링크를 통해 해결했다.

https://stackoverflow.com/a/50375317/12857153

 

찾아보니 typeORM cli에서 entity를 쓰려면 그 entity가 js파일이어야 하는데

typeORM init 시 생성해주는 ormconfig의 entities설정이 .ts로 되어 있어서 해당 에러가 발생하는거였다..

//ormconfig.json
module.exports = {
  type: "mysql",
  host: "localhost",
  port: 3306,
  username: "user",
  password: "password",
  database: "database",
  synchronize: true,
  logging: false,
  entities: ["src/entity/**/*.ts"],
  migrations: ["src/migration/**/*.ts"],
  cli: {
    entitiesDir: "src/entity",
    migrationsDir: "src/migration",
    subscribersDir: "src/subscriber",
  },
};

 

그래서 위 코드를 아래와 같이 ormconfig에서 접근하는 entity의 위치를 ts빌드 완료 후의 위치로 변경해줬더니 에러를 해결할 수 있었다.

//ormconfig.json
module.exports = {
  type: "mysql",
  host: "localhost",
  port: 3306,
  username: "user",
  password: "password",
  database: "database",
  synchronize: true,
  logging: false,
  entities: ["build/entity/**/*.js"], //수정한 부분
  migrations: ["build/migration/**/*.js"], //얘도 js로 바꿔줘야 함
  cli: {
    entitiesDir: "src/entity",
    migrationsDir: "src/migration",
    subscribersDir: "src/subscriber",
  },
};

 

후에 보니 공식홈페이지에는 js로 쓰여 있었다....

init 시 자동생성되는 파일에는 왜 ts로 적어둔거야...

https://typeorm.io/#/migrations/creating-a-new-migration

 

+참고사항

ts빌드를 build디렉토리에다가 했기 때문에 entities: ["build/entity/**/*.js"] 라고 해줬지만

ts빌드를 다른 디렉토리에 하지 않거나 빌드하는 디렉토리의 위치가 다르면 수정 내용을 위와 같이 하면 안된다.

//tsconfig.json
{
  "compilerOptions": {
    "lib": ["es5", "es6"],
    "target": "ES2015",
    "module": "commonjs",
    "strict": true,
    "esModuleInterop": false,

    "forceConsistentCasingInFileNames": true /* Disallow inconsistently-cased references to the same file. */,
    "moduleResolution": "node",
    "outDir": "./build", //ts compile했을때 생기는 js파일을 저장할 디렉토리
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "sourceMap": true
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules"]
}

 

2-2. migration error 2

위 에러의 해결 방법: 글로벌 typeorm을 사용한다..!

https://github.com/typeorm/typeorm/issues/2450#issuecomment-402005655

 

글로벌 typeorm을 사용하는 방법

1. 주소 직접 입력

$ ./node_modules/.bin/typeorm migration:run

 

2. npx 사용

$ npx typeorm migration:run

1, 2번의 결과는 같다.

 

3. 기타사항

구글링 하다가 typeORM 공식 github레포의 내용을 검색할 수 있게 만들어 둔 사이트를 발견했다!!

https://typeorm.delightful.studio/index.html

너무좋아!!!!!