[web2py] Re: Getting table a to use as default string from field in table b

[tsvim]

db.define_table('table_settings',
                Field('name','string'),
                Field('default_value','string'))

db.define_table('data',
                
Field('parent_table',db.table_settings,writable=False,readable=False),
                Field('datetime','datetime',default=request.now),
                Field('title','string'),
                Field('value','string'))

db.data.value.default = db.table_settings['parent_table'].default_value
db.table_settings.default_value.requires = IS_IN_SET(['a','b'])