Support enum for DB who don't support it

[antoine-pous]

Currently SQLite doesn't have ENUM type, but TypeORM can use it's own validator before inserting a value into the DB and emit an error when the value is not in the enum.

enum MyEnum { 
    zero = 0; 
    one = 1;
}

@Entity()
export class Test {
    @Column({enum: MyEnum})
    myVar: number; // Must be 0 or 1
}

[mhombach]

I'm a big fan of making ORM-Systems really universal or at least as much universal as it can get.
If i create my business-logic within it and i later need to change the database-engine, then there should not be a bunch of stuff i need to change. Sure, i can then optimize everything for the new engine, but it should "work" flawless without changing much stuff...
So i would vote for implementing this as universal type into the ORM and when a database doenst support that column-type, then internally it should just get converted to a string or an integer, which represents that ENUM values. And sure, then it should be validated exactly to match the declared ENUM-Object.

[pleerock]

@mhombach sorry to disappoint you, but Im biggest anti-fun of universal ORM-systems, simply because:

• any abstraction come with cost, and cost of making everything universal is too high - you loose to much functionality that each database provides which values higher then having things "universal", because of...
• being universal is mostly useless, because in practice it does not give anything except of "i later need to change the database-engine". But reality that you are not going to change your database engine almost never. And if you'll have such need ever it will be easier to you to change all places in your code to match new database rather then loosing benefits provided by point 1

But this particular feature request we can implement, because it does not restrict / limit us in anything, its just an addition.

[atheros]

I once wrote a full app using an orm(not typeorm) using linux + mysql for in-house usage, then my boss came and told me I have to deploy same app to one of our clients. The catch was it was supposed to run on windows with mssql. Obviously it took me some time to get the job done and I would have greatly appreciated if the orm I was using would allow me to abstract things more.

In any case since there is already simple-array and simple-json, why not add simple-enum? Also an option with "useNativeTypeIfAvailable" would be even better.

[pleerock]

This issue is opened for the community. Feel free to implement simple-enum type, its easy feature to implement.

[davidmpaz]

My 5 cents...

@antoine-pous I came into this issue a couple of day before looking for the same kind of functionality. The outcome of it did not look well so i tried to solve it working around. I am working with cordova and sqljs drivers. So, what I did was this:

// CostType.ts
export enum CostType {
    TOTAL = 'total',
    TAX_TOTAL = 'taxTotal',
    GRANT_TOTAL = 'grantTotal'
}

// CostEntryOrmModel.ts
@Entity('costEntry')
export class CostEntryOrmModel {

    @PrimaryGeneratedColumn()
    identifier: number;

    // note here how the type is specified to be the type of value in enum
    @Column({type: 'varchar'})
    id: CostType;

    // .....
}

Would this work for you? Can you give it a try and report back your feedback?

If I find time this week I can make a pull request with some tests to make a PoC

Cheers

[maxxims]

@borremosch could you please provide an example for this implementation?

I am mostly interested for the MSSQL.

export enum CostType { TOTAL = 0, TAX_TOTAL = 1, GRANT_TOTAL = 2 }

export class CostEntryOrmModel {
    @PrimaryGeneratedColumn()
    id: number;
    @Column({type: 'simple-enum'})
    cost: CostType;
}

This is saved as nvarchar and I don't see any CHECK Constraints being added.

[borremosch]

@maxxims you'll have to add the enum type to the column decorator as well, just like with a regular enum:

@Column({
    type: 'simple-enum',
    enum: CostType
})
cost: CostType;

Hope this solves it

[SYip]

Should this issue be closed as #3700 was already merged?