Seperated Change Tracking Policies and Partial Objects from Configuration Chapter, Finished XML Mapping Chapter with a reference on all tags and attributes
This commit is contained in:
Benjamin Eberlei
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@ -12,6 +12,8 @@
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+ DQL (Doctrine Query Language)
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+ Query Builder
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+ Native SQL
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+ Change Tracking Policies
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+ Partial Objects
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+ XML Mapping
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+ YAML Mapping
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+ Annotations Reference
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@ -245,180 +245,6 @@ or an instance of `Doctrine\DBAL\Connection`. If an array is passed it is direct
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DBAL Factory `Doctrine\DBAL\DriverManager::getConnection()`. The DBAL configuration is explained
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in the [DBAL section](./../../../../../dbal/2.0/docs/reference/configuration/en).
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++ Change Tracking Policies
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Change tracking is the process of determining what has changed in managed
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entities since the last time they were synchronized with the database.
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Doctrine provides 3 different change tracking policies, each having its
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particular advantages and disadvantages. The change tracking policy can
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be defined on a per-class basis (or more precisely, per-hierarchy).
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+++ Deferred Implicit
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The deferred implicit policy is the default change tracking policy and the most
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convenient one. With this policy, Doctrine detects the changes by a
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property-by-property comparison at commit time and also detects changes
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to entities or new entities that are referenced by other managed entities
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("persistence by reachability"). Although the most convenient policy, it can
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have negative effects on performance if you are dealing with large units of
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work (see "Understanding the Unit of Work"). Since Doctrine can't know what
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has changed, it needs to check all managed entities for changes every time you
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invoke EntityManager#flush(), making this operation rather costly.
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+++ Deferred Explicit
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The deferred explicit policy is similar to the deferred implicit policy in that
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it detects changes through a property-by-property comparison at commit time. The
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difference is that only entities are considered that have been explicitly marked
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for change detection through a call to EntityManager#persist(entity) or through
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a save cascade. All other entities are skipped. This policy therefore gives
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improved performance for larger units of work while sacrificing the behavior
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of "automatic dirty checking".
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Therefore, flush() operations are potentially cheaper with this policy. The
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negative aspect this has is that if you have a rather large application and
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you pass your objects through several layers for processing purposes and
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business tasks you may need to track yourself which entities have changed
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on the way so you can pass them to EntityManager#persist().
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This policy can be configured as follows:
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[php]
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/**
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* @Entity
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* @ChangeTrackingPolicy("DEFERRED_EXPLICIT")
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*/
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class User
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{
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// ...
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}
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+++ Notify
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This policy is based on the assumption that the entities notify interested
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listeners of changes to their properties. For that purpose, a class that
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wants to use this policy needs to implement the NotifyPropertyChanged?
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interface from the Doctrine\Common namespace. As a guideline, such an
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implementation should look as follows:
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[php]
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use Doctrine\Common\NotifyPropertyChanged,
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Doctrine\Common\PropertyChangedListener;
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/**
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* @Entity
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* @ChangeTrackingPolicy("NOTIFY")
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*/
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class MyEntity implements NotifyPropertyChanged
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{
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// ...
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private $_listeners = array();
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public function addPropertyChangedListener(PropertyChangedListener $listener)
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{
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$this->_listeners[] = $listener;
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}
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protected function _onPropertyChanged($propName, $oldValue, $newValue)
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{
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if ($this->_listeners) {
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foreach ($this->_listeners as $listener) {
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$listener->propertyChanged($this, $propName, $oldValue, $newValue);
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}
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}
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}
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}
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Then, in each property setter of this class or derived classes, you need to
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invoke `_onPropertyChanged` as follows to notify listeners:
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[php]
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// ...
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class MyEntity implements NotifyPropertyChanged
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{
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// ...
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public function setData($data)
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{
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if ($data != $this->data) {
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$this->_onPropertyChanged('data', $this->data, $data);
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$this->data = $data;
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}
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}
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}
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The check whether the new value is different from the old one is not mandatory
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but recommended. That way you also have full control over when you consider a
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property changed.
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The negative point of this policy is obvious: You need implement an interface
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and write some plumbing code. But also note that we tried hard to keep this
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notification functionality abstract. Strictly speaking, it has nothing to do
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with the persistence layer and the Doctrine ORM or DBAL. You may find that
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property notification events come in handy in many other scenarios as well.
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As mentioned earlier, the `Doctrine\Common` namespace is not that evil and
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consists solely of very small classes and interfaces that have almost no
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external dependencies (none to the DBAL and none to the ORM) and that you
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can easily take with you should you want to swap out the persistence layer.
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This change tracking policy does not introduce a dependency on the Doctrine
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DBAL/ORM or the persistence layer.
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The positive point and main advantage of this policy is its effectiveness. It
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has the best performance characteristics of the 3 policies with larger units of
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work and a flush() operation is very cheap when nothing has changed.
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++ Partial Objects
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A partial object is an object whose state is not fully initialized after being
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reconstituted from the database and that is disconnected from the rest of its data. The following section will describe why partial objects are problematic and what the approach of Doctrine2 to this problem is.
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> **NOTE**
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> The partial object problem in general does not apply to methods or
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> queries where you do not retrieve the query result as objects. Examples are:
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> `Query#getArrayResult()`, `Query#getScalarResult()`, `Query#getSingleScalarResult()`,
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> etc.
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+++ What is the problem?
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In short, partial objects are problematic because they are usually objects with
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broken invariants. As such, code that uses these partial objects tends to be
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very fragile and either needs to "know" which fields or methods can be safely
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accessed or add checks around every field access or method invocation. The same
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holds true for the internals, i.e. the method implementations, of such objects.
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You usually simply assume the state you need in the method is available, after
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all you properly constructed this object before you pushed it into the database,
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right? These blind assumptions can quickly lead to null reference errors when
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working with such partial objects.
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It gets worse with the scenario of an optional association (0..1 to 1). When
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the associated field is NULL, you dont know whether this object does not have
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an associated object or whether it was simply not loaded when the owning object
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was loaded from the database.
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These are reasons why many ORMs do not allow partial objects at all and instead
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you always have to load an object with all its fields (associations being proxied).
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One secure way to allow partial objects is if the programming language/platform
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allows the ORM tool to hook deeply into the object and instrument it in such a
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way that individual fields (not only associations) can be loaded lazily on first
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access. This is possible in Java, for example, through bytecode instrumentation.
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In PHP though this is not possible, so there is no way to have "secure" partial
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objects in an ORM with transparent persistence.
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Doctrine, by default, does not allow partial objects. That means, any query that only selects partial object data and wants to retrieve the result as objects
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(i.e. `Query#getResult()`) will raise an exception telling you that
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partial objects are dangerous. If you want to force a query to return you partial objects, possibly as a performance tweak, you can use the `partial` keyword as follows:
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[php]
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$q = $em->createQuery("select partial u.{id,name} from MyApp\Domain\User u");
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+++ When should I force partial objects?
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Mainly for optimization purposes, but be careful of premature optimization as partial objects
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lead to potentially more fragile code.
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++ Proxy Objects
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A proxy object is an object that is put in place or used instead of the "real" object. A proxy object can add behavior to the object being proxied without that object being aware of it. In Doctrine 2, proxy objects are used to realize several features but mainly for transparent lazy-loading.
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@ -15,8 +15,11 @@ The XML driver is backed by an XML Schema document that describes the structure
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The XML mapping document of a class is loaded on-demand the first time it is requested and subsequently stored in the metadata cache. In order to work, this requires certain conventions:
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* Each entity/mapped superclass must get its own dedicated XML mapping document.
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* The name of the mapping document must consist of the fully qualified name of the class, where namespace separators are replaced by dots (.).
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* All mapping documents should get the extension ".dcm.xml" to identify it as a Doctrine mapping file. This is more of a convention and you are not forced to do this. You can change the file extension easily enough.
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* The name of the mapping document must consist of the fully qualified name of the class, where namespace
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separators are replaced by dots (.). For example an Entity with the fully qualified class-name "MyProject\Entities\User"
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would require a mapping file "MyProject.Entities.User.dcm.xml" unless the extension is changed.
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* All mapping documents should get the extension ".dcm.xml" to identify it as a Doctrine mapping file. This is more of
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a convention and you are not forced to do this. You can change the file extension easily enough.
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-
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@ -26,8 +29,8 @@ The XML mapping document of a class is loaded on-demand the first time it is req
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It is recommended to put all XML mapping documents in a single folder but you can spread the documents over several folders if you want to. In order to tell the XmlDriver where to look for your mapping documents, supply an array of paths as the first argument of the constructor, like this:
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[php]
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// $config instanceof Doctrine\ORM\Configuration
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$driver = new \Doctrine\ORM\Mapping\Driver\XmlDriver(array('/path/to/files'));
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$config = new \Doctrine\ORM\Configuration();
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$driver = new \Doctrine\ORM\Mapping\Driver\XmlDriver(array('/path/to/files1', '/path/to/files2'));
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$config->setMetadataDriverImpl($driver);
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@ -38,46 +41,469 @@ As a quick start, here is a small example document that makes use of several com
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[xml]
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// Doctrine.Tests.ORM.Mapping.User.dcm.xml
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<?xml version="1.0" encoding="UTF-8"?>
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<doctrine-mapping xmlns="http://doctrine-project.org/schemas/orm/doctrine-mapping"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://doctrine-project.org/schemas/orm/doctrine-mapping
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/Users/robo/dev/php/Doctrine/doctrine-mapping.xsd">
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http://www.doctrine-project.org/schemas/orm/doctrine-mapping.xsd">
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<entity name="Doctrine\Tests\ORM\Mapping\User" table="cms_users">
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<indexes>
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<index name="name_idx" columns="name"/>
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<index columns="user_email"/>
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</indexes>
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<unique-constraints>
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<unique-constraint columns="name,user_email" name="search_idx" />
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</unique-constraints>
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<lifecycle-callbacks>
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<lifecycle-callback type="prePersist" method="onPrePersist" />
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<lifecycle-callback type="prePersist" method="doStuffOnPrePersist"/>
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<lifecycle-callback type="prePersist" method="doOtherStuffOnPrePersistToo"/>
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<lifecycle-callback type="postPersist" method="doStuffOnPostPersist"/>
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</lifecycle-callbacks>
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<id name="id" type="integer" column="id">
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<generator strategy="AUTO"/>
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<sequence-generator sequence-name="tablename_seq" allocation-size="100" initial-value="1" />
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</id>
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<field name="name" column="name" type="string" length="50"/>
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<field name="name" column="name" type="string" length="50" nullable="true" unique="true" />
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<field name="email" column="user_email" type="string" column-definition="CHAR(32) NOT NULL" />
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<one-to-one field="address" target-entity="Address">
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<join-column name="address_id" referenced-column-name="id"/>
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<one-to-one field="address" target-entity="Address" inversed-by="user">
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<cascade><cascade-remove /></cascade>
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<join-column name="address_id" referenced-column-name="id" on-delete="CASCADE" on-update="CASCADE"/>
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</one-to-one>
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<one-to-many field="phonenumbers" target-entity="Phonenumber" mapped-by="user">
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<cascade>
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<cascade-persist/>
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</cascade>
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<order-by>
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<order-by-field name="number" direction="ASC" />
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</order-by>
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</one-to-many>
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<many-to-many field="groups" target-entity="Group">
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<cascade>
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<cascade-all/>
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</cascade>
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<join-table name="cms_users_groups">
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<join-columns>
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<join-column name="user_id" referenced-column-name="id"/>
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<join-column name="user_id" referenced-column-name="id" nullable="false" unique="false" />
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</join-columns>
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<inverse-join-columns>
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<join-column name="group_id" referenced-column-name="id"/>
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<join-column name="group_id" referenced-column-name="id" column-definition="INT NULL" />
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</inverse-join-columns>
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</join-table>
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</many-to-many>
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</entity>
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</doctrine-mapping>
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Be aware that class-names specified in the XML files should be fully qualified.
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Be aware that class-names specified in the XML files should be fully qualified.
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++ XML-Element Reference
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The XML-Element reference explains all the tags and attributes that the Doctrine Mapping XSD Schema defines.
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You should read the Basic-, Association- and Inheritance Mapping chapters to understand what each of this
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definitions means in detail.
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+++ Defining an Entity
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Each XML Mapping File contains the definition of one entity, specified as the `<entity />` element
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as a direct child of the `<doctrine-mapping />` element:
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[xml]
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<doctrine-mapping>
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<entity name="MyProject\User" table="cms_users" repository-class="MyProject\UserRepository">
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<!-- definition here -->
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</entity>
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</doctrine-mapping>
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Required attributes:
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* name - The fully qualified class-name of the entity.
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Optional attributes:
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* table - The Table-Name to be used for this entity. Otherwise the Unqualified Class-Name is used by default.
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* repository-class - The fully qualified class-name of an alternative `Doctrine\ORM\EntityRepository` implementation to be used with this entity.
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* inheritance-type - The type of inheritance, defaults to none. A more detailed description follows in the *Defining Inheritance Mappings* section.
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+++ Defining Fields
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Each entity class can contain zero to infinite fields that are managed by Doctrine. You can define
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them using the `<field />` element as a children to the `<entity />` element. The field element is only
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used for primitive types that are not the ID of the entity. For the ID mapping you have to use the `<id />` element.
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[xml]
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<entity name="MyProject\User">
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<field name="name" type="string" length="50" />
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<field name="username" type="string" unique="true" />
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<field name="age" type="integer" nullable="true" />
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<field name="isActive" column="is_active" type="boolean" />
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<field name="weight" type="decimal" scale="5" precision="2" />
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</entity>
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Required attributes:
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* name - The name of the Property/Field on the given Entity PHP class.
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Optional attributes:
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* type - The `Doctrine\DBAL\Types\Type` name, defaults to "string"
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* column - Name of the column in the database, defaults to the field name.
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* length - The length of the given type, for use with strings only.
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* unique - Should this field contain a unique value across the table? Defaults to false.
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* nullable - Should this field allow NULL as a value? Defaults to false.
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* version - Should this field be used for optimistic locking? Only works on fields with type integer or datetime.
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* scale - Scale of a decimal type.
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* precision - Precision of a decimal type.
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* column-definition - Optional alternative SQL representation for this column. This definition begin after the
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field-name and has to specify the complete column definition. Using this feature will turn this field dirty
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for Schema-Tool update commands at all times.
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+++ Defining Identity and Generator Strategies
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An entity has to have at least one `<id />` element. For composite keys you can specify more than one id-element,
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however surrogate keys are recommended for use with Doctrine 2. The Id field allows to define properties of
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the identifier and allows a subset of the `<field />` element attributes:
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[xml]
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<entity name="MyProject\User">
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<id name="id" type="integer" column="user_id" />
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</entity>
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Required attributes:
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* name - The name of the Property/Field on the given Entity PHP class.
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* type - The `Doctrine\DBAL\Types\Type` name, preferably "string" or "integer".
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Optional attributes:
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* column - Name of the column in the database, defaults to the field name.
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Using the simplified definition above Doctrine will use no identifier strategy for this entity. That means
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you have to manually set the identifier before calling `EntityManager#persist($entity)`. This is the
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so called `ASSIGNED` strategy.
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If you want to switch the identifier generation strategy you have to nest a `<generator />` element inside
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the id-element. This of course only works for surrogate keys. For composite keys you always have to use
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the `ASSIGNED` strategy.
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[xml]
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<entity name="MyProject\User">
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<id name="id" type="integer" column="user_id">
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<generator strategy="AUTO" />
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</id>
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</entity>
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The following values are allowed for the `<generator />` strategy attribute:
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* AUTO - Automatic detection of the identifier strategy based on the preferred solution of the database vendor.
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* IDENTITY - Use of a IDENTIFY strategy such as Auto-Increment IDs available to Doctrine AFTER the INSERT statement has been executed.
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* SEQUENCE - Use of a database sequence to retrieve the entity-ids. This is possible before the INSERT statement is executed.
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If you are using the SEQUENCE strategy you can define an additional element to describe the sequence:
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[xml]
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<entity name="MyProject\User">
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<id name="id" type="integer" column="user_id">
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<generator strategy="SEQUENCE" />
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<sequence-generator sequence-name="user_seq" allocation-size="5" initial-value="1" />
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</id>
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</entity>
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Required attributes for `<sequence-generator />`:
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* sequence-name - The name of the sequence
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Optional attributes for `<sequence-generator />`:
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* allocation-size - By how much steps should the sequence be incremented when a value is retrieved. Defaults to 1
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* initial-value - What should the initial value of the sequence be.
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> **NOTE**
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>
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> If you want to implement a cross-vendor compatible application you have to specify <generator strategy="AUTO" /> and
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> additionaly define the <sequence-generator /> element, if Doctrine chooses the sequence strategy for a platform.
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+++ Defining a Mapped Superclass
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Sometimes you want to define a class that multiple entities inherit from, which itself is not an entity however.
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The chapter on *Inheritance Mapping* describes a Mapped Superclass in detail. You can define it in XML using
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the `<mapped-superclass />` tag.
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[xml]
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<doctrine-mapping>
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<mapped-superclass name="MyProject\BaseClass">
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<field name="created" type="datetime" />
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<field name="updated" type="datetime" />
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</mapped-superclass>
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</doctrine-mapping>
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||||
|
||||
Required attributes:
|
||||
|
||||
* name - Class name of the mapped superclass.
|
||||
|
||||
You can nest any number of `<field />` and unidirectional `<many-to-one />` or `<one-to-one />` associations inside
|
||||
a mapped superclass.
|
||||
|
||||
+++ Defining Inheritance Mappings
|
||||
|
||||
There are currently two inheritance persistence strategies that you can choose from when defining entities that
|
||||
inherit from each other. Single Table inheritance saves the fields of the complete inheritance hierachy in a single table,
|
||||
joined table inheritance creates a table for each entity combining the fields using join conditions.
|
||||
|
||||
You can specify the inheritance type in the `<entity />` element and then use the `<discriminator-column />` and
|
||||
`<discriminator-mapping />` attributes.
|
||||
|
||||
[xml]
|
||||
<entity name="MyProject\Animal" inheritance-type="JOINED">
|
||||
<discriminator-column name="discr" type="string" />
|
||||
<discriminator-map>
|
||||
<discriminator-mapping value="cat" class="MyProject\Cat" />
|
||||
<discriminator-mapping value="dog" class="MyProject\Dog" />
|
||||
<discriminator-mapping value="mouse" class="MyProject\Mouse" />
|
||||
</discriminator-map>
|
||||
</entity>
|
||||
|
||||
The allowed values for inheritance-type attribute are `JOINED` or `SINGLE_TABLE`.
|
||||
|
||||
> **NOTE**
|
||||
>
|
||||
> All inheritance related definitions have to be defined on the root entity of the hierachy.
|
||||
|
||||
+++ Defining Lifecycle Callbacks
|
||||
|
||||
You can define the lifecycle callback methods on your entities using the `<lifecycle-callbacks />` element:
|
||||
|
||||
[xml]
|
||||
<entity name="Doctrine\Tests\ORM\Mapping\User" table="cms_users">
|
||||
|
||||
<lifecycle-callbacks>
|
||||
<lifecycle-callback type="prePersist" method="onPrePersist" />
|
||||
</lifecycle-callbacks>
|
||||
</entity>
|
||||
|
||||
+++ Defining One-To-One Relations
|
||||
|
||||
You can define One-To-One Relations/Assocations using the `<one-to-one />` element. The required
|
||||
and optional attributes depend on the associations being on the inverse or owning side.
|
||||
|
||||
For the inverse side the mapping is as simple as:
|
||||
|
||||
[xml]
|
||||
<entity class="MyProject\User">
|
||||
<one-to-one field="address" target-entity="Address" mapped-by="user" />
|
||||
</entity>
|
||||
|
||||
Required attributes for inverse One-To-One:
|
||||
|
||||
* field - Name of the property/field on the entitys PHP class.
|
||||
* target-entity - Name of the entity associated entity class. If this is not qualified the namespace of the current class is prepended.
|
||||
* mapped-by - Name of the field on the owning side (here Address entity) that contains the owning side association.
|
||||
|
||||
For the owning side this mapping would look like:
|
||||
|
||||
[xml]
|
||||
<entity class="MyProject\Address">
|
||||
<one-to-one field="user" target-entity="User" inversed-by="address" />
|
||||
</entity>
|
||||
|
||||
Required attributes for owning One-to-One:
|
||||
|
||||
* field - Name of the property/field on the entitys PHP class.
|
||||
* target-entity - Name of the entity associated entity class. If this is not qualified the namespace of the current class is prepended.
|
||||
|
||||
Optional attributes for owning One-to-One:
|
||||
|
||||
* inversed-by - If the association is bidirectional the inversed-by attribute has to be specified with the name of the field on the inverse entity that contains the back-reference.
|
||||
* orphan-removal - If true, the inverse side entity is always deleted when the owning side entity is. Defaults to false.
|
||||
* fetch - Either LAZY or FETCH, defaults to LAZY. This attribute makes only sense on the owning side, the inverse side *ALWAYS* has to use the `FETCH` strategy.
|
||||
|
||||
The definition for the owning side relies on a bunch of mapping defaults for the join column names.
|
||||
Without the nested `<join-column />` element Doctrine assumes to foreign key to be called `user_id` on the Address
|
||||
Entities table. This is because the `MyProject\Address` entity is the owning side of this association, which means
|
||||
it contains the foreign key.
|
||||
|
||||
The completed explictly defined mapping is:
|
||||
|
||||
[xml]
|
||||
<entity class="MyProject\Address">
|
||||
<one-to-one field="user" target-entity="User" inversed-by="address">
|
||||
<join-column name="user_id" referenced-column-name="id" />
|
||||
</one-to-one>
|
||||
</entity>
|
||||
|
||||
+++ Defining Many-To-One Associations
|
||||
|
||||
The many-to-one association is *ALWAYS* the owning side of any bidirectional association. This simplifies the mapping
|
||||
compared to the one-to-one case. The minimal mapping for this association looks like:
|
||||
|
||||
[xml]
|
||||
<entity class="MyProject\Article">
|
||||
<many-to-one field="author" target-entity="User" />
|
||||
</entity>
|
||||
|
||||
Required attributes:
|
||||
|
||||
* field - Name of the property/field on the entitys PHP class.
|
||||
* target-entity - Name of the entity associated entity class. If this is not qualified the namespace of the current class is prepended.
|
||||
|
||||
Optional attributes:
|
||||
|
||||
* inversed-by - If the association is bidirectional the inversed-by attribute has to be specified with the name of the field on the inverse entity that contains the back-reference.
|
||||
* orphan-removal - If true the entity on the inverse side is always deleted when the owning side entity is and it is not connected to any other owning side entity anymore. Defaults to false.
|
||||
* fetch - Either LAZY or FETCH, defaults to LAZY.
|
||||
|
||||
This definition relies on a bunch of mapping defaults with regards to the naming of the join-column/foreign key. The
|
||||
explictly defined mapping includes a `<join-column />` tag nested inside the many-to-one association tag:
|
||||
|
||||
[xml]
|
||||
<entity class="MyProject\Article">
|
||||
<many-to-one field="author" target-entity="User">
|
||||
<join-column name="author_id" referenced-column-name="id" />
|
||||
</many-to-one>
|
||||
</entity>
|
||||
|
||||
The join-column attribute `name` specifies the column name of the foreign key and
|
||||
the `referenced-column-name` attribute specifies the name of the primary key column
|
||||
on the User entity.
|
||||
|
||||
+++ Defining One-To-Many Associations
|
||||
|
||||
The one-to-many association is *ALWAYS* the inverse side of any association. There exists no such thing as a
|
||||
uni-directional one-to-many association, which means this association only ever exists for bi-directional associations.
|
||||
|
||||
[xml]
|
||||
<entity class="MyProject\User">
|
||||
<one-to-many field="phonenumbers" target-entity="Phonenumber" mapped-by="user" />
|
||||
</entity>
|
||||
|
||||
Required attributes:
|
||||
|
||||
* field - Name of the property/field on the entitys PHP class.
|
||||
* target-entity - Name of the entity associated entity class. If this is not qualified the namespace of the current class is prepended.
|
||||
* mapped-by - Name of the field on the owning side (here Phonenumber entity) that contains the owning side association.
|
||||
|
||||
Optional attributes:
|
||||
|
||||
* fetch - Either LAZY or FETCH, defaults to LAZY.
|
||||
|
||||
+++ Defining Many-To-Many Associations
|
||||
|
||||
From all the associations the many-to-many has the most complex definition. When you rely on the mapping defaults
|
||||
you can omit many definitions and rely on their implicit values.
|
||||
|
||||
[xml]
|
||||
<entity class="MyProject\User">
|
||||
<many-to-many field="groups" target-entity="Group" />
|
||||
</entity>
|
||||
|
||||
Required attributes:
|
||||
|
||||
* field - Name of the property/field on the entitys PHP class.
|
||||
* target-entity - Name of the entity associated entity class. If this is not qualified the namespace of the current class is prepended.
|
||||
|
||||
Optional attributes:
|
||||
|
||||
* mapped-by - Name of the field on the owning side that contains the owning side association if the defined many-to-many association is on the inverse side.
|
||||
* inversed-by - If the association is bidirectional the inversed-by attribute has to be specified with the name of the field on the inverse entity that contains the back-reference.
|
||||
* fetch - Either LAZY or FETCH, defaults to LAZY.
|
||||
|
||||
The mapping defaults would lead to a join-table with the name "User_Group" being created that contains two columns
|
||||
"user_id" and "group_id". The explicit definition of this mapping would be:
|
||||
|
||||
[xml]
|
||||
<entity class="MyProject\User">
|
||||
<many-to-many field="groups" target-entity="Group">
|
||||
<join-table name="cms_users_groups">
|
||||
<join-columns>
|
||||
<join-column name="user_id" referenced-column-name="id"/>
|
||||
</join-columns>
|
||||
<inverse-join-columns>
|
||||
<join-column name="group_id" referenced-column-name="id"/>
|
||||
</inverse-join-columns>
|
||||
</join-table>
|
||||
</many-to-many>
|
||||
</entity>
|
||||
|
||||
Here both the <join-columns> and <inverse-join-columns> tags are necessary to tell Doctrine for which side the
|
||||
specified join-columns apply. These are nested inside a `<join-table />` attribute which allows to specify
|
||||
the table name of the many-to-many join-table.
|
||||
|
||||
+++ Cascade Element
|
||||
|
||||
Doctrine allows cascading of several UnitOfWork operations to related entities. You can specifiy the cascade
|
||||
operations in the `<cascade />` element inside any of the association mapping tags.
|
||||
|
||||
[xml]
|
||||
<entity class="MyProject\User">
|
||||
<many-to-many field="groups" target-entity="Group">
|
||||
<cascade>
|
||||
<cascade-all/>
|
||||
</cascade>
|
||||
</many-to-many>
|
||||
</entity>
|
||||
|
||||
Besides `<cascade-all />` the following operations can be specifed by their respective tags:
|
||||
|
||||
* <cascade-persist />
|
||||
* <cascade-merge />
|
||||
* <cascade-remove />
|
||||
* <cascade-refresh />
|
||||
|
||||
+++ Join Column Element
|
||||
|
||||
In any explicitly defined association mapping you will need the `<join-column />` tag. It defines how the
|
||||
foreign key and primary key names are called that are used for joining two entities.
|
||||
|
||||
Required attributes:
|
||||
|
||||
* name - The column name of the foreign key.
|
||||
* referenced-column-name - The column name of the associated entities primary key
|
||||
|
||||
Optional attributes:
|
||||
|
||||
* unique - If the join column should contain a UNIQUE constraint. This makes sense for Many-To-Many join-columns only to simulate a one-to-many unidirectional using a join-table.
|
||||
* nullable - should the join column be nullable, defaults to true.
|
||||
* on-delete - Foreign Key Cascade action to perform when entity is deleted, defaults to NO ACTION/RESTRICT but can be set to "CASCADE".
|
||||
|
||||
+++ Defining Order of To-Many Associations
|
||||
|
||||
You can require one-to-many or many-to-many associations to be retrieved using an additional `ORDER BY`.
|
||||
|
||||
[xml]
|
||||
<entity class="MyProject\User">
|
||||
<many-to-many field="groups" target-entity="Group">
|
||||
<order-by>
|
||||
<order-by-field name="name" direction="ASC" />
|
||||
</order-by>
|
||||
</many-to-many>
|
||||
</entity>
|
||||
|
||||
+++ Defining Indexes or Unique Constraints
|
||||
|
||||
To define additional indexes or unique constraints on the entities table you can use the
|
||||
`<indexes />` and `<unique-constraints />` elements:
|
||||
|
||||
[xml]
|
||||
<entity name="Doctrine\Tests\ORM\Mapping\User" table="cms_users">
|
||||
|
||||
<indexes>
|
||||
<index name="name_idx" columns="name"/>
|
||||
<index columns="user_email"/>
|
||||
</indexes>
|
||||
|
||||
<unique-constraints>
|
||||
<unique-constraint columns="name,user_email" name="search_idx" />
|
||||
</unique-constraints>
|
||||
</entity>
|
||||
|
||||
You have to specify the column and not the entity-class field names in the index and unique-constraint
|
||||
definitions.
|
||||
Loading…
Reference in New Issue
Block a user