From b21faef5b995c8ac69d753ed74192fb20882818c Mon Sep 17 00:00:00 2001 From: zYne Date: Thu, 14 Jun 2007 15:56:01 +0000 Subject: [PATCH] --- manual/new/docs/en/working-with-objects.txt | 30 ++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/manual/new/docs/en/working-with-objects.txt b/manual/new/docs/en/working-with-objects.txt index d315d99de..42a1f5203 100644 --- a/manual/new/docs/en/working-with-objects.txt +++ b/manual/new/docs/en/working-with-objects.txt @@ -1,3 +1,31 @@ ++ Dealing with relations ++ Component overview -++ Fetching objects +++ Fetching objects ++++ Field lazy-loading + +Whenever you fetch an object that has not all of its fields loaded from database then the state of this object is called proxy. Proxy objects can load the unloaded fields lazily. + +Lets say we have a User class with the following definition: + + +class User extends Doctrine_Record +{ + public function setTableDefinition() + { + $this->hasColumn('name', 'string', 20); + $this->hasColumn('password', 'string', 16); + $this->hasColumn('description', 'string'); + } +} + + +In the following example we fetch all the Users with the fields name and password loaded directly. Then we lazy-load a huge field called description for one user. + + +$users = Doctrine_Query::create()->select('u.name, u.password')->from('User u'); + +// the following lazy-loads the description fields and executes one additional database query +$users[0]->description; + + +Doctrine does the proxy evaluation based on loaded field count. It does not evaluate which fields are loaded on field-by-field basis. The reason for this is simple: performance. Field lazy-loading is very rarely needed in PHP world, hence introducing some kind of variable to check which fields are loaded would introduce unnecessary overhead to basic fetching.