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Trevor,

Such check could be useful on alembic side too. Good opportunity for
contribution.

Andrew.


On Fri, Jan 31, 2014 at 6:12 AM, Trevor McKay <tmckay at redhat.com> wrote:

> Okay,  I can accept that migrations shouldn't be supported on sqlite.
>
> However, if that's the case then we need to fix up savanna-db-manage so
> that it checks the db connection info and throws a polite error to the
> user for attempted migrations on unsupported platforms. For example:
>
> "Database migrations are not supported for sqlite"
>
> Because, as a developer, when I see a sql error trace as the result of
> an operation I assume it's broken :)
>
> Best,
>
> Trevor
>
> On Thu, 2014-01-30 at 15:04 -0500, Jay Pipes wrote:
> > On Thu, 2014-01-30 at 14:51 -0500, Trevor McKay wrote:
> > > I was playing with alembic migration and discovered that
> > > op.drop_column() doesn't work with sqlite.  This is because sqlite
> > > doesn't support dropping a column (broken imho, but that's another
> > > discussion).  Sqlite throws a syntax error.
> > >
> > > To make this work with sqlite, you have to copy the table to a
> temporary
> > > excluding the column(s) you don't want and delete the old one, followed
> > > by a rename of the new table.
> > >
> > > The existing 002 migration uses op.drop_column(), so I'm assuming it's
> > > broken, too (I need to check what the migration test is doing).  I was
> > > working on an 003.
> > >
> > > How do we want to handle this?  Three good options I can think of:
> > >
> > > 1) don't support migrations for sqlite (I think "no", but maybe)
> > >
> > > 2) Extend alembic so that op.drop_column() does the right thing (more
> > > open-source contributions for us, yay :) )
> > >
> > > 3) Add our own wrapper in savanna so that we have a drop_column()
> method
> > > that wraps copy/rename.
> > >
> > > Ideas, comments?
> >
> > Migrations should really not be run against SQLite at all -- only on the
> > databases that would be used in production. I believe the general
> > direction of the contributor community is to be consistent around
> > testing of migrations and to not run migrations at all in unit tests
> > (which use SQLite).
> >
> > Boris (cc'd) may have some more to say on this topic.
> >
> > Best,
> > -jay
> >
> >
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>
>
>
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