Again, if just focused on form validation, I suppose another option would be
to use an onvalidation function (processed after form validation but before
db insert).
Anthony
On Tuesday, October 11, 2011 7:23:33 AM UTC-4, Anthony wrote:
>
> On Tuesday, October 11, 2011 4:04:41 AM UTC-4, spyker wrote:
>>
>> I have several tables where there should only be one possible combination
>> of two uuid-fields per table (mostly many to many links).
>>
>> I have created 'unique' constraints for those fields in Postgresql so the
>> database would not accept any inserts or edits which violates that
>> constraint.
>>
>> I use that in combination with 'try:.. except:' to insert data.
>>
>> Can DAL be used in a way for this? As far as I understand the
>> IS_NOT_IN_DB validators that it is working on form-level and not on database
>> level and I am not sure whether it can be used for a combination of fields
>> (unless I do it with a computed field - which will use up a lot of extra
>> resources).
>
>
> If you only need to validate form submissions (and not other means of
> making inserts), then you could do something like:
>
> db.define_table('mytable',
> Field('field1'),
> Field('field2',
> requires=IS_NOT_IN_DB(db(db.mytable.field1==request.vars.field1),
> 'mytable.field2')))
>
> That will make sure field2 is unique among the set of records where field1
> matches the new value of field1 being inserted (so the combination of field1
> and field2 must be unique). It depends on the values being available in
> request.vars, so not relevant for non-form inserts (though in that case, I
> suppose you could create your own request.vars as a hack).
>
> Anthony
>
>
>
>
>
