如何从关系中只获取列名

Question

How to join column, that when i launch my function, he return me only columns name instead of entity_columnName .

I'm using TypeORM, and i try this;

const data = this.conn.getRepository(User).createQueryBuilder('user');
data.leftJoinAndSelect('user.orders', 'orders');
data.getRawMany();

but return me:

firstName: ...
lastName: ...
age: ...
order_name: ...
order_price: ...

instead of:

firstName: ...
lastName: ...
age: ...
name: ...
price: ...

can someone tell me how do this? thanks for any help

Answer 1

How are your User and Order entities defined?

If you define a relation (eg OneToMany) with the eager: true option, then TypeORM will automatically include the related entities when you query using the repository *find methods. It won't do this when you use the QueryBuilder, where you have to add them such as with leftJoinAndSelect() (as you have done).

An example from an Invoice entity that has OneToMany line items:

  @OneToMany(
    () => InvoiceLineItem,
    (item: InvoiceLineItem) => item.invoice,
    { eager: true }
  )
  items: InvoiceLineItem[]

Per the example, if I were then to find() or findMany() invoices, then the related objects, items will be included as well because eager: true .

This behaviour might translate well to your situation with users and orders.

Also be aware of the differences between getMany() and getRawMany() when using the query builder.

If you use getMany() then TypeORM will automagically give you entities back (eg you'd get an instance of User with property orders that is an array of Order instances). The property names will be correct.

Since you added the NestJS tag to your question, also understand serialization: https://docs.nestjs.com/techniques/serialization

There is a built-in ClassSerializerInterceptor that comes with NestJS that you might find useful.

In your controller you can decorate the class or any of its methods eg

@UseInterceptors(ClassSerializerInterceptor)

This will transform the response to JSON, and will apply the rules specified with class-transformer decorators on the entity/DTO class.

If you were to use this interceptor, the response sent to the client will have your desired property names.

If you really want to modify the response that your client gets back, you can also look into writing your own Interceptor.