Question on Many to many handling

Hi, is there any complete example on how to handle CRUD operation in models with many to many relation? I'm new to PHP and the Yii guide only gave me a vague idea for this problem.

Since the relationship between the Post model and the Tag model of the blog demo is MANY_MANY, you can investigate the code of it.

Thanks, I've looked through the blog demo code and see that we must handle the tag table manually also there are no transaction used in the example, can we use transaction on more than one model?