[Dbix-class] Re: Template creates objects via belongs_to (how to lay out relationships)

[Matt Rosin]

Hello,

I'm the person who started this thread on the Catalyst ML. 

The original problem is that trying to display the field of an object related by belongs_to, Template Toolkit would autovivify the object if it didn't already exist. So given a Transaction object r, just trying to display r.customer.b_company would do an sql insert and create a blank customer object, if the column r.customer was 0 (i.e. if there was no customer object).

The docs did not explain that such side-effects were entailed by "doing the right thing". It seemed to be a bug to me but I understand now it is more just a problem with the docs. The might_have docs are also a bit lacking in fact one sentence stops midway through.

It seems my options are to do one of the following.
1. Allow NULL for that column so belongs_to knows it is optional. 
2. Use might_have instead of belongs_to, if there is no other difference in its operation.
3. Solve it all in the search call before going to the template. Maybe same autovivification will happen though.
4. Create a dummy customer of ID 0.

My original reasoning for not allowing NULL is so that I wouldn't get a crash if trying to display/reference a null. Since it will be operated by someone not familiar with the concept of NULL it seemed a bit dangerous to use it. At any rate now I have a system in production and don't want to make big changes to it. probably #4 is simplest but also I would like to know if might_have can be used as a drop-in replacement for belongs_to that just won't do autovivification. Thanks for your help.

Sincerely,

Matt Rosin


       
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