[EntitySchema] Extend BaseSchema

Issue type:

[x] question [ ] bug report [ ] feature request [x] documentation issue

Database system/driver:

[ ] cordova [ ] mongodb [ ] mssql [ ] mysql / mariadb [ ] oracle [x] postgres [ ] sqlite [ ] sqljs [ ] react-native [ ] expo

TypeORM version:

[x] latest [ ] @next [ ] 0.x.x (or put your version here)

Steps to reproduce or a small repository showing the problem:

Dear TypeORM maintainers and community,

first of all, i would like to thank you for this awesome project - i really like using TypeORM… Recently, I stumbled upon EntitySchema for decoupling the “database structure” from the actual models - and i like this approach very much!

Before, when using the normal Entity Decorators, i did something like this in order to DRY up my boilerplate code for my entities:

export abstract class AbstractEntity {
  @PrimaryGeneratedColumn('uuid') id: string;
  @CreateDateColumn() createdAt: Date;
  @UpdateDateColumn() updatedAt: Date;
}

export class Category extends AbstractEntity {
   @Column() slug: string;
   // ...
}

When switching to EntitySchema, i found, that there is some kind of extends param, which can be used to extend an existing Schema (see code here) https://github.com/typeorm/typeorm/blob/b9d2756c1726728da85c36aeedd924230dc601e6/src/entity-schema/EntitySchemaOptions.ts#L13-L18

However, I did not find any real documentation about this feature so far - not even in the sample.

Basically, what i would like to do, is something like this:

export const BaseSchema = new EntitySchema({
  name: 'BaseSchema',
  columns: {
    id: {
      type: 'uuid',
      generated: 'uuid',
      primary: 'true',
    },
    // ... more default column descriptions here
  },
  // maybe some other "default" descriptions here
});

and then “use” this schema as blueprint for other schemas, like so:

export const CategorySchema = new EntitySchema<Category>({
  name: 'Category',
  tablename: 'categories',
  extends: 'BaseSchema',
  columns: {
    slug: {
      type: 'varchar',
      length: 50,
      unique: true,
    }
  }
});

so that the CategorySchema inherits all columns that are described in the BaseSchema. However, this does not work - if i run the dev server (synchronize: true to automatically migrate everything), this does not work…

Maybe you can point me to the right direction? That would be awesome 👍

In order to give something back, i would then update the documentation for the EntitySchema, because this lacks documentation…

All the best and thanks a lot for your time and effort!

[johannesschobel]

Ok, just an information for anyone, who may be stumbling upon the same issue here: In order to “include” some kind of BaseColumns to an EntitySchema, you may need to define them as follows:

import { EntitySchemaColumnOptions } from 'typeorm';

export const BaseColumnsSchemaPart = {
  id: {
    type: 'uuid',
    primary: true,
    generated: 'uuid',
  } as EntitySchemaColumnOptions,

  createdAt: {
    name: 'created_at',
    type: 'timestamp with time zone',
    createDate: true,
  } as EntitySchemaColumnOptions,
  
  updatedAt: {
    name: 'updated_at',
    type: 'timestamp with time zone',
    updateDate: true,
  } as EntitySchemaColumnOptions,
};

Then, in your “regular” schema file, include it like this:

export const UserSchema = new EntitySchema<User>({
  name: 'UserSchema',
  tableName: 'users',

  columns: {
    ...BaseColumnsSchemaPart,

    email: {
      type: 'varchar',
      length: 150,
      unique: true,
    },
    // ... more columns may be defined here...
  },
  // other options like relations, ... 
});

[pleerock]

we don’t need extends in there. Just use object spread/rest syntax and you’ll get more than just extension, e.g.

 columns: {
    id: {
      type: 'uuid',
      generated: 'uuid',
      primary: 'true',
    },
   ...commonColumns,
   ...etc
}