Random ids in sqlalchemy (pylons)

Question

I\'m using pylons and sqlalchemy and I was wondering how I could have some randoms ids as primary_key.

Answer 1

i use this pattern and it works pretty good. source

from sqlalchemy import types
from sqlalchemy.databases.mysql import MSBinary
from sqlalchemy.schema import Column
import uuid


class UUID(types.TypeDecorator):
    impl = MSBinary
    def __init__(self):
        self.impl.length = 16
        types.TypeDecorator.__init__(self,length=self.impl.length)

    def process_bind_param(self,value,dialect=None):
        if value and isinstance(value,uuid.UUID):
            return value.bytes
        elif value and not isinstance(value,uuid.UUID):
            raise ValueError,'value %s is not a valid uuid.UUID' % value
        else:
            return None

    def process_result_value(self,value,dialect=None):
        if value:
            return uuid.UUID(bytes=value)
        else:
            return None

    def is_mutable(self):
        return False


id_column_name = "id"

def id_column():
    import uuid
    return Column(id_column_name,UUID(),primary_key=True,default=uuid.uuid4)

#usage
my_table = Table('test',metadata,id_column(),Column('parent_id',UUID(),ForeignKey(table_parent.c.id)))

Though zzzeek I believe is the author of sqlalchemy, so if this is wrong he would know, and I would listen to him.