On Mon, Jun 15, 2009 at 9:33 PM, erikj <[email protected]> wrote:
>
> I would advise the use of sqlalchemy-migrate, it takes some
> time to get it up and running and get used to it, but it's well
> worth the effort.
Hi,
thank you very much, sqlalchemy-migrate seems useful and the linked
documentation is very interesting.
However, this doesn't solve all of my problems... migrate requires you to
write an upgrade() and downgrade() functions, to describe the changes
introduced in a version of the database; but I not able to write such
functions.
For example, let's say I have a db with a single table:
class Person(Entity):
name = Field(Text)
surname = Field(Text)
and I want to add an additional table, with a OneToMany relationship:
class Person(Entity):
name = Field(Text)
surname = Field(Text)
favorite_movie = OneToMany('Movie')
class Movie(Entity):
title = Field(Text)
fans = ManyToOne('Person')
now, how would you do the migration without dropping down the table, and
loosing all the data in it?
I could manually alter the Person table, but I am not sure on what would be
exactly the structure that elixir expects.
For the moment I have solved this by only using ManyToMany (which may be
good for what I need to do), but I wonder if there is some guideline for
doign this with elixir, or if you have any suggestion.
cheers
>
> http://code.google.com/p/sqlalchemy-migrate/
>
> The nice thing is that it keeps track of the 'revision' of
> your database schema. So you can develop everything against
> your test db, and once you put your app in production at
> multiple sites or at new sites, you just run the upgrade command,
> and your db is ready.
>
> for difficult migrations, you can always use plain sql
> commands using engine.execute('alter table ...')
>
> as for the recipe on the elixir website on using sqlalchemy-migrate,
> it's not really complete...
>
> regards,
>
> Erik
>
> On Jun 15, 5:11 pm, "Giovanni Marco Dall'Olio" <[email protected]>
> wrote:
> > Hi,
> > this question has been already asked in this list one year ago, but I
> would
> > like to know if it has changed in the mean time.
> >
> > So, what is the best way to alter a table structure with elixir?
> > In particular, I want to add a new table, and some OneToMany and
> ManyToMany
> > relationships to it in the existing tables.
> > This could be done manually, but I am not sure on how to do it and keep
> it
> > compatible with elixir and how to make elixir recognize it later.
> >
> > --
> > Giovanni Dall'Olio, phd student
> > Department of Biologia Evolutiva at CEXS-UPF (Barcelona, Spain)
> >
> > My blog on bioinformatics:http://bioinfoblog.it
> >
>
--
Giovanni Dall'Olio, phd student
Department of Biologia Evolutiva at CEXS-UPF (Barcelona, Spain)
My blog on bioinformatics: http://bioinfoblog.it
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