UUID Column and Type decorator about sqlalchemy-utils HOT 6 CLOSED

Good job with this one too!

Some suggestions:

1. As with #12, I think we should not override basic column syntax (atleast not in this case). We can just pass the uuid type parameters for the type object constructor:

import uuid
import sqlalchemy as sa
from sqlalchemy_utils.types import UUIDType

class ModelWithType(Base):
    id = sa.Column(
        UUIDType(version=4), 
        primary_key=True, 
    )

1. Some users may want to store the UUID as VARCHAR(32), this should also be configuration option.
2. MSSQL should use GUID datatype (looking at mssql dialect of sqlalchemy it seems it does not support this datatype atm). Maybe we could add this later?

The implementation could closely resemble this: http://docs.sqlalchemy.org/en/rel_0_8/core/types.html#backend-agnostic-guid-type

However let's use the name UUIDType instead of GUID. GUID is just a name for Microsoft's own datatype that implements UUID spec.

from sqlalchemy-utils.

My only reservation with making this a type is I can't quite wrap my head around how to make UUIDType(auto=True) work as the default argument is on sa.Column(). Would we just return a new uuid from the bind method on the type if null is passed?

from sqlalchemy-utils.

What do we want to achieve with auto=True? Is it sufficient if the uuid values are assigned at pre-flush phase? If so I would just make another listener to SA-Utils which would assign uuids to all transient object's UUIDType auto columns.

Something like this:

def auto_assign_uuids(session, flush_context, instances):
    for obj in session.new:
        for prop in obj.__mapper__.iterate_properties:
            if not isinstance(prop. sa.orm.ColumnProperty):
                continue
            if isinstance(prop.columns[0].type, UUIDType):
                setattr(obj, prop.key, uuid())

from sqlalchemy-utils.

That looks sufficient. The point is for primary_keys that are UUIDs. I don't want to have to import uuid and specify default=uuid.uuid4 on each one.

from sqlalchemy-utils.

The more that I think about this we could actually make this part of SQLAlchemy-Defaults (https://github.com/kvesteri/sqlalchemy-defaults). Let's make a default rule there: all columns which are primary keys and UUIDType have column default uuid.uuid4

from sqlalchemy-utils.

Moving to #26

from sqlalchemy-utils.