Question: How to make the default value of two different datetime fields match?

Hi all!

How to make the default value of two different datetime fields match?

Say I have the following BaseModel:

class BaseModel(Model):
    id = CharField(primary_key=True, default=lambda: shortuuid.uuid())
    created_at = DateTimeTZField(default=lambda: dt.now(tz))
    updated_at = DateTimeTZField(default=lambda: dt.now(tz))

Now, when the object is created/instantiated, the values in created_at and updated_at will have slightly different timestamps (which is completely understandable).

What would be the ideal approach to make sure they match 100% when an object is first created?

I initially tried using DateTimeTZField(constraints=[SQL('DEFAULT CURRENT_TIMESTAMP')]) instead, but when creating a new record (eg: BaseModel.create()), Peewee will try to insert created_at and updated_at as NULL, which will override the DB server default. Then I thought that maybe I could use pre_init or pre_save signals to explicitly set instance.updated_at = instance.created_at, which works, but I thought there might be a better way to accomplish this.

Thank you in advance!

[coleifer]

I don’t know what evolve is. It’s not part of this library. Database-provided defaults work just fine with peewee, as do python-side defaults.

[jonathanmach]

Sorry @coleifer, I thought peewee db evolve was part of this library. Thanks very much for your help!