Thetypeandlengthvalidationsarehandybutmostofthetimethey're not enough. ThereforeDoctrine provides some mechanisms that can be used to validate your data in more detail.<br /><br />Validators: Validators are an easy way to specify further validations. Doctrine has a lot of predefinedvalidators that are frequently needed such as email, country, ip, range and regexp validators. Youfind a full list of available validators at the bottom of this page. You can specify which validatorsapply to which column through the 4th argument of the hasColumn() method.If that is still not enough and you need some specialized validation that is not yet available asa predefined validator you have three options:<br /><br />- You can write the validator on your own.<br />- You can propose your need for a new validator to a Doctrine developer.<br />- You can use validation hooks.<br /><br />The first two options are advisable if it is likely that the validation is of general useand is potentially applicable in many situations. In that case it is a good idea to implement
a new validator. However if the validation is special it is better to use hooks provided by Doctrine:<br /><br />- validate() (Executed every time the record gets validated)<br />- validateOnInsert() (Executed when the record is new and gets validated)<br />- validateOnUpdate() (Executed when the record is not new and gets validated)<br /><br />If you need a special validation in your active recordyou can simply override one of these methods in your active record class (a descendant of Doctrine_Record).Within thess methods you can use all the power of PHP to validate your fields. When a field
doesnt pass your validation you can then add errors to the record'serrorstack.Thefollowingcodesnippetshowsanexampleofhowtodefinevalidatorstogetherwithcustomvalidation:<br/>