[Sqlalchemy-tickets] Issue #3216: Don't create serial column when there's more than one PK column (zzzeek/sqlalchemy)

[thiefmaster <iss...@bi...>]

New issue 3216: Don't create serial column when there's more than one PK column
https://bitbucket.org/zzzeek/sqlalchemy/issue/3216/dont-create-serial-column-when-theres-more

thiefmaster:

E.g. in this example:

```
class Foo(Base):                                   
    __tablename__ = 'foo'
    id1 = Column(Integer, primary_key=True, nullable=False)
    id2 = Column(Integer, primary_key=True, nullable=False)
```

I believe it does not make much sense to create `id1` as autoincrement/serial while `id2` is a plain integer columns.

Unless there are database engines which actually support multiple serial columns, I would either disable autoincrement for both columns in that case or raise an error, forcing the user to enable/disable autoincrement explictly.