web2py representation 'format' in grandchi

问题:

The q&a here (and the doc) describe the use of the format= argument to the define_table function. I have a problem getting that to work in a slightly more complicated case. I'm using web2py version (1, 99, 7, datetime.datetime(2012, 3, 4, 22, 12, 8), 'stable'), and Python 2.5.4. (I'm using MySQL, but I assume that's irrelevant.)

I have the following:

'Independent' (not a child) tables Institution and Person. Table Team is a child of Institution. Table Team_staff connects Person and Team together. Here's a trimmed version:

db.define_table('Person',
                Field('First_name', 'string', length=60, required=True),
                Field('Last_name', 'string', length=60, required=True),
                ...
                format='%(First_name)s %(Last_name)s')

db.define_table('Institution',
                Field('Institution_name', 'string', length=60, required=True,
                   unique=True),
                format='%(Institution_name)s')

db.define_table('Team',
                Field('Institution', db.Institution),
                Field('Sex', 'string', required=True,
                   requires=IS_IN_SET(['m', 'f'])),
                Field('Level', 'string', required=True),
                ...
                format='%(Institution)s %(Sex)s')

db.define_table('Team_staff',
                Field('Team', db.Team),
                Field('Team_staff_member', db.Person),
                ...
                Field('Team_position', 'string', required=True))

So far, so good. I have a controller that creates a SQLFORM(db.Team_staff), and a view that simply displays the form. When I drop down the 'Team' dropdown, I see the Institution id concatenated with the 'sex' value (such as 1 f, then 1 m below that, then 2 f, and so forth). As Institution has format='%(Institution_name)s', why am I not seeing the institution name instead of the institution id?

回答1:

The "format" attribute does not propagate across tables that way. Instead, you should be able to define the "format" attribute as a lambda function, which takes a row of the table as its argument:

db.define_table('Team', ...,
    format=lambda r: '%s %s' % (db.Institution[r.Institution].Institution_name,
                                r.Sex))