How to set default value for datetime in nest ORM column for mysql

Issue type:

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

Database system/driver:

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

TypeORM version:

[ ] latest [ ] @next [x] 0.2.18 (or put your version here)

Steps to reproduce or a small repository showing the problem:

Does anyone know how to set default value of datetime type for nest ORM mysql I tried

@Column({ type: 'datetime', default: () => new Date()}) .
@Column({ type: 'datetime', default: () => '2019-06-29'})
@Column({ type: 'datetime', default: 'CURRENT_TIMESTAMP'})
@Column({ type: 'datetime', default: 'now()'})

All failed.

I will be very appreciated for any help.

[robertmain]

Yeah, you probably don’t want to do that, because that default value is evaluated only when the migration is run. So what you’re effectively doing is snapshotting the current time when the migration is being run, then telling MySQL to always use that value as the default value. So what you’re effectively running is this:

@Column({
  nullable: false,
  default: () => new Date(2020, 1, 18, 17, 00), 
  type: 'timestamp',
})

Which will produce something like the following SQL:

ADD COLUMN `mycolumnname` TIMESTAMP NOT NULL DEFAULT '2020-02-18 17:00:00-05:00'

Meaning that every time you insert data into your table, your column will ALWAYS have the default value of '2020-02-18 17:00:00-05:00' irrespective of what the actual current date/time are.

What you probably want to do is have MySQL re-calculate that value every time, so you want to shoot for the following SQL:

ADD COLUMN `mycolumnname` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP

I’m guessing at this point because I’ve migrated most of my apps to postgres, but you probably want something like this in your column definition:

@Column({
  nullable: false,
  default: () => 'CURRENT_TIMESTAMP' 
  type: 'timestamp',
})

[robertmain]

MySQL does…but TypeORM’s integration with MySQL may not. It’s hard to say, but I ended up switching to postgres (for a variety of reasons). I know that “jUSt SwITch tO PosTGrES” isn’t really a solution, but if you can it tends to be a much better developer experience all round 😃