Re: [SQLObject] Best way to order columns

[Ian B. <ia...@co...>]

On Thu, 2003-07-10 at 14:37, Mark Melvin wrote:
> Yes, of course.  Perhaps I am using things in a bad way.  In order to 
> generate column labels for a list control I am iterating through the 
> SQLObject._columns attribute, pulling out .kw['name'] for each one.  It is 
> a list in a particular order, which I assume is used to generate the 
> select() statement because the order appears to match.  It does not appear 
> to match the order in which the columns are created in my particular class. 
>  I guess I should look at the source to see how this _columns list is 
> created and go from there.

It is probably sorted by the order of the hashes of the strings used to
name the objects, i.e., effectively unsorted.  When you do:

class Something(SQLObject):
    fname = Col()
    lname = Col()

SQLObject (MetaSQLObject to be particular) looks through the classes
*dictionary*, which is of course unordered.  If you want to order them
more naturally, you'll have to add another attribute that contains that
ordering (like order=['fname', 'lname']), or do it alphabetically or
something.

I suppose a slightly hackish solution would be to make Col objects
remember what order they were instantiated in.  I'm not sure if that's
evil or convenient.

> Cool.  I have re-architected my LEFT JOINed approach to be a single table 
> and I am finding SQLObject pretty sweet.  Simplifying my first case helped 
> me a lot to get started, and it should be easier to extend to more 
> complicated cases.  I found the documentation - while good, is missing a 
> lot of the little things.  I found myself doing a dir() on object a lot to 
> figure out what was in there.

A lot of stuff that is not documented is an unstable interface.  You're
welcome to use it of course (I'm a firm opponent of double-underscore
private variables), but be warned it may change.  If there's something
in particular that you think is important, bring it up and perhaps we
can make a stable interface for it.

It sounds like you are doing some introspection, which is something in
particular that I have put off until I have a better feel for how it
should work.

  Ian