On Dec 10, 2013, at 12:00 AM, Matthew Pounsett <matt.pouns...@gmail.com> wrote:
> I'm trying to work with the postgres ARRAY type and I'm having a hard time
> figuring out what I'm doing wrong with filtering queries on the array column.
> Here's some sample code, omitting the session setup:
>
> class MyTable(Base):
>
> __tablename__ = 'mytable'
> id = Column(Integer, primary_key=True)
>
> myset = Column(sqlalchemy.dialects.postgresql.ARRAY(String))
>
>
> Base.metadata.create_all(engine)
>
>
>
> z = ['a', 'b', 'c']
>
>
> match = session.query(MyTable).\
>
> filter(MyTable.myset == z).\
>
> all()
>
>
that’s a little strange but you can get around it using CAST:
match = session.query(MyTable).\
filter(MyTable.myset == cast(z, ARRAY(String))).\
all()
though maybe there’s a better operator to use for array == array comparison,
not sure
of course if you declare you column like this:
myset = Column(ARRAY(Text))
it works…..in Postgresql there’s no real difference between TEXT and VARCHAR
(which is unusual). Not sure why PG can’t cast between array of VARCHAR vs.
TEXT but I bet there’s some info on the web about that, it’s unusual PG would
have a problem with something like that (though a google seems to confirm it).
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