[Sqlalchemy-tickets] Issue #4317: MSSQL TIMESTAMP as primary_key error on Insert (zzzeek/sqlalchemy)

[Pinguin P. <iss...@bi...>]

New issue 4317: MSSQL TIMESTAMP as primary_key error on Insert
https://bitbucket.org/zzzeek/sqlalchemy/issues/4317/mssql-timestamp-as-primary_key-error-on

Pinguin Pinguin:

```
#!python

class Inventur(base.Base):
    __tablename__ = 't341'

    item = Column('item', Integer, primary_key=False)
    ts = Column('ts', TIMESTAMP(convert_int=False), primary_key=True)


    __table_args__ = (
    )


article_inventur = Inventur(
    item=123,
)
session.add(article_inventur)
session.flush()

```


SAWarning: Column 't341.ts' is marked as a member of the primary key for table 't341', but has no Python-side or server-side default generator indicated, nor does it indicate 'autoincrement=True' or 'nullable=True', and no explicit value is passed.  Primary key columns typically may not store NULL.

TIMESTAMP is an auto value