Suppose I have Town model and Customer model
I want to delete Town id 100, but there are several Customer records with FK town_id 100
So in this case user should not be allowed to delete Town id 100 as it will break Customer records.
How can I enable this functionality? (user should be presented with an error message)
Simple if/else statement
records = Look-up customers where town_id = 100 (probably using count)
if (there are some records)
call the delete function
Try using the STAT relation http://www.yiiframework.com/doc/guide/database.arr#statistical-query the example can easily be changed…
You should do this at the database level too.