Doctrine is an Object Relational Mapper (ORM) written for the PHP programming language. First off, for those who don’t know, an ORM is programming technique of connecting objects to the data stored in a relational database. What this provides is an object based method of modifying and interacting with the database instead of writing sql queries.

I do not want to go into the details as to the pros and cons of using an ORM but for those of you creating websites and applications that utilize relational databases then utilizing an ORM can save you a lot of grief writing and maintaining sql queries. Some key benefits to using Doctrine are listed below:

• Search
  Doctrine includes an interface for easily performing searches on specified properties of your objects.
• Data Validation
  In addition to Database level validation, Doctrine has built in validation so that you will get exceptions at the php level before a DB query is performed.
• Dynamic Query Language (DQL)
  In addition to utilizing your defined objects for interacting with the data, Doctrine has its own advanced query language to easily pull objects based on its relationships and parameters.
• Event Listeners
  Doctrine has built in support for listening to events on the query, record, and connection level.  This allows you to easily add in functionality before and/or after  inserts, updates, deletes, etc.
• Pagination utility
  pagination of data is a common functionality of websites. Doctrine comes with a highly customizable pager package to easily setup pagers within your site.

To learn more about Doctrine head on over to their website, check out the User Documentation,  or jump right in by following along with their My First Project Tutorial.