[BUG] FK columns have wrong length when PrimaryGeneratedColumn('uuid') is used.

[AntonioAngelino]

Issue type:

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

Database system/driver:

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

TypeORM version:

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

Description

PrimaryGeneratedColumn('uuid') generates a VARCHAR(36) mysql column.
One-to-one, one-to-many and many-to-many relations generate VARCHAR(255) columns instead.

Steps to reproduce:

• Create the following entities and check the generated DDL.

class Author {
    @PrimaryGeneratedColumn('uuid')
    id: string;
}

class Post {
    @PrimaryGeneratedColumn('uuid')
    id: string;

  @ManyToOne(type => Author)
  @JoinColumn()
  author: Author;
}

CREATE TABLE author
(
  id VARCHAR(36) NOT NULL PRIMARY KEY,
)
  ENGINE = InnoDB;

CREATE TABLE post
(
  id VARCHAR(36)  NOT NULL PRIMARY KEY,
 authorId VARCHAR(255) NULL,
CONSTRAINT FK_9466682df91534dd95e4dbaa616 FOREIGN KEY (authorId) REFERENCES author (id)
)
  ENGINE = InnoDB;

[tomtwo]

In version 0.2.18 I'm still seeing an issue related to this when manually adding a userId field to my entity like this:

class Order extends BaseEntity {
  @ManyToOne(type => User, user => user.orders)
  user: User;

  @Column()
  userId: string;
}

The id column for User is a varchar(36), however the userId column in this other table becomes varchar(255). This can be overridden by using @Column({ length: 36}), but I guess it makes sense to fix this in typeorm?

[tomtwo]

I want to be able to read the value of userId without joining the whole user. The pattern comes from the docs here:

https://github.com/typeorm/typeorm/blob/master/docs/relations-faq.md#how-to-use-relation-id-without-joining-relation