Doctrine_manual-1-2-en

Chapter 9: DQL (Doctrine Query Language) 120
Chapter 9
DQL (Doctrine Query Language)
Introduction
Doctrine Query Language (DQL) is an Object Query Language created for helping users in
complex object retrieval. You should always consider using DQL (or raw SQL) when retrieving
relational data efficiently (eg. when fetching users and their phonenumbers).
In this chapter we will execute dozens of examples of how to use the Doctrine Query
Language. All of these examples assume you are using the schemas defined in the previous
chapters, primarily the Defining Models (page 53) chapter. We will define one additional
model for our testing purposes:
Listing
9-1
// models/Account.php
class Account extends Doctrine_Record
{
public function setTableDefinition()
{
$this->hasColumn('name', 'string', 255);
$this->hasColumn('amount', 'decimal');
}
}
Here is the same example in YAML format. You can read more about YAML in the YAML
Schema Files (page 195) chapter:
Listing
9-2
---
# schema.yml
# ...
Account:
columns:
name: string(255)
amount: decimal
When compared to using raw SQL, DQL has several benefits:
• From the start it has been designed to retrieve records(objects) not result set rows
• DQL understands relations so you don't have to type manually sql joins and join
conditions
• DQL is portable on different databases
----------------- Brought to you by