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Created 6 years ago by fsb – Tips – 5 comments – viewed 41,122 times
( +16 / -1 )
There are situations in which Active Record will generate nonsense queries from what a nieve Yii user might think is reasonable code. One such situation is a CActiveDataProvider using CDbCriteria to get data from parent and 1:n child table with a condition on the child table.
Relational databases do not support inheritance so if we need to represent it, we have to somehow store meta info while keeping performance by minimizing JOINs. One way to solve this problem is using single table inheritance. All fields for the whole class tree are stored in a single table. Class name is stored in the type field of the same table.
Please, note. This article is entirely based on a work done by me colleague developer, who hasn't got account on this webpage and also hasn't got time for writing this article. I'm writing it for him. I will try to forward him any comments that may appear, but can't assure if/when he'll be able to answer. I'm far, far less experienced in Oracle therefore I won't probably be able to help myself.