Added simple-enum column type

[borremosch]

I have added the simple-enum column type discussed in #1414. It works like this:

• For MySQL, MariaDB and Postgres, the native ENUM type is used
• For SQLite and SQL Server, a CHECK() constraint is used, like so:

    colname CHECK (colname in ('A','B','C')) NOT NULL DEFAULT ('A')
  

  The CHECK is also reverse engineered back into an enum when code is being generated from a DB schema
• For Oracle, I found that enum is currently not supported in TypeORM. Since Oracle does have a native ENUM type, I believe simple-enum should be based on it. I have not added simple-enum for Oracle.

[pleerock]

since sqlite supports enum now, it should have enum type as well

[pleerock]

also, don't forget to list new types in the docs (website)

[pleerock]

or using CHECK constraint in sqlite can't be called enum ?

[borremosch]

I cannot find native enum support on the SQLite website: https://www.sqlite.org/datatype3.html.

I would say it makes sense to have enum for native enum types, and simple-enum for the emulated enum type. That way it will be more clear when you are using a derived/emulated type.

[borremosch]

There is currently no section on either enums or simple- types on the website. Do you want me to create one in a pull request?

Also, are you aware that the website certificate is invalid when accessing it from https://typeorm.io/?

[pleerock]

Also, are you aware that the website certificate is invalid when accessing it from https://typeorm.io/?

yes =(

There is currently no section on either enums or simple- types on the website. Do you want me to create one in a pull request?

yes feel free please

[janpio]

2 other simple- types are now mentioned, but simple-enum is not:
https://typeorm.io/entities#simple-array-column-type
#10077

[pleerock]

Great work! Asking @AlexMesser for review

[pleerock]

Thank you so much!

[toonvanstrijp]

@borremosch thanks! :)

[JVMartin]

Found a bug in this PR, that prevents me from using a protected word like "from" as the column name. For example:

export enum FromType {
  NO_REPLY = 'no-reply',
  RANDOM = 'random',
}

@Entity('broadcast')
class BroadcastEntity {
  @PrimaryGeneratedColumn()
  id: number;

  @Column({
    type: 'simple-enum',
    enum: FromType,
    nullable: false,
  })
  from: FromType;
}

Here's the error:

  console.log ../node_modules/typeorm/platform/PlatformTools.js:200
    query failed: CREATE TABLE "broadcast" ("id" integer PRIMARY KEY AUTOINCREMENT NOT NULL, "from" varchar CHECK( from IN ('no-reply','random') ) NOT NULL)

  console.log ../node_modules/typeorm/platform/PlatformTools.js:200
    error: [Error: SQLITE_ERROR: near "from": syntax error] {
      errno: 1,
      code: 'SQLITE_ERROR'
    }

As you can see, the generated column:
"from" varchar CHECK( from IN ('no-reply','random') ) NOT NULL
is missing the double quotes that should be surrounding the column name, and so a protected keyword like from cannot be used.

It should look like this:
"from" varchar CHECK( "from" IN ('no-reply','random') ) NOT NULL

(The column name must be wrapped in double-quotes.)

This was in sqlite, if that matters.

[opgbaudouin]

When using simple-enum and using 'synchronise' in the connection options i get a continuous "column has changed errors" (i.e. it keeps ALTER table).

   //simple-enum causes TypeORM to think columns have always changed...
   @Column({name: 'type'/*, type: 'simple-enum', enum: ProjectType*/}) 
   @IsEnum(ProjectType) //class-validator
    type: ProjectType;

Removing it naturally removes the CHECK IN feature but there is some error in detecting if a column schema is the same and should be altered.

This is in TypeORM 0.2.25 and SQLite 3 adapter 4.2.0.