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.
Created 6 years ago by fsb – Tips – 5 comments – viewed 40,198 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.
Created 4 years ago by Boaz – Tips – 0 comments – viewed 24,039 times
( +5 / -1 )
When you're filling up a form of a CActiveRecord (using CActiveForm for example), usually you'll construct your code so that in case of validation error you'll get back the form with the error displayed back to you, typically when CActiveForm.errorSummary() is used. This is how its done by Gii.
One of the common tasks the web application might be required to perform, especially the app using some kind of a CMS, is to save the history of data changes. Your client for sure will want the answer to this simple question - If I mess this up or delete by accident can we bring it back? Well, DB backup is one thing and quick recovery is another - let's talk about latter one.