CDbTransaction insensitive to the database, or depends on implementation of the database? In other words, the transaction database engine is used, or in Yii implements its own transaction engine? That is, If the database type MyISAM, then CDbTransaction will work or not?

i think transaction only supported to innodb

That’s correct. Transactions only rollback if you are using InnoDB (but the inserts/updates will still go in if you are using MyIsam).

Just fyi: There are more storage engines than just InnoDb which support transactions. PBXT for example. Also: You do not need to convert all your tables to InnoDB/PBXT to make transactions work. It’s sufficient if you only convert those touched by your transactions.

I have enough knowledge about a MySQL functionality. I only want to know the CDbTransaction is self-sufficient mechanism or it is only a wrap around DBMS features.

It wraps the DBMS using PDO transactions.