Here's what I propose:
In define_table, at this point:
if migrate:
sql_locker.acquire()
try:
t._create(migrate=migrate, fake_migrate=fake_migrate)
finally:
sql_locker.release()
At the end, it can read the database schema and see if it contains all
the columns needed in the cPickle .table file. If not, it can output
something like "Sorry, database table %s needs column %s to look like
%s, this needs a manual fix".
Is this right? I'm not sure how to read a database table schema
programmatically. Is this different for each db? Hopefully it's at
least easy for postgresql.
On Nov 18 2009, 11:46 am, mdipierro <mdipie...@cs.depaul.edu> wrote:
> Yes, I would.
>
> On Nov 18, 2:03 am,toomim<too...@gmail.com> wrote:
>
>
>
> > Thanks! Would you accept a patch that makes the error messages more
> > obvious in these situations where you need to manually edit the
> > tables?
>
> > I think ROR and Django's approaches to migrations (fully-specifying
> > deltas vs. maintaining static schemas) are both more burdensome than
> > web2py's system of "semi-automatic for most changes (adding columns &
> > tables) but manual for major changes". But the "manual for major
> > changes" part needs better error messages with suggestions for how to
> > proceed.
>
> > On Nov 14, 8:04 pm, mdipierro <mdipie...@cs.depaul.edu> wrote:
>
> > > You are changing a "text" column (Field) into an "ineteger" column. My
> > > changing the type web2py assumes you want to keep the data and yet it
> > > cannot convert "text" to "integert". You have to do the migration in
> > > two steps: 1) remove the column (comment it and run appadmin) 2) add
> > > the column again with the new type. In this case web2py understands
> > > you do not want to keep the data and will not attempt to do it.
>
> > > On Nov 14, 7:08 pm,toomim<too...@gmail.com> wrote:
>
> > > > I routinely run into migration problems. I suspect this happens when I
> > > > change a column's datatype, or when I remove a table from db.py and
> > > > then later make a new table with the same name as the old one.
>
> > > > In these situations, the migrations get messed up and I get
> > > > stacktraces in sql.py with errors like:
>
> > > > ProgrammingError: column "study__tmp" is of type integer but
> > > > expression is of type text
> > > > LINE 1: UPDATE actions SET study__tmp=study;
> > > > ^
> > > > HINT: You will need to rewrite or cast the expression.
>
> > > > How can I migrate in these situations?
>
> > > > As an aside, I love the automatic migrations when they work, but I
> > > > don't mind writing sql to fix the underlying database when they don't.
> > > > Could web2py just tell me what schema it expects, let me fix the
> > > > database, and then let me say "OK web2py, the database is ready to go!"
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