UPGRADE_TO_2_0

# Upgrade from 2.0-ALPHA4 to 2.0-BETA1

## EntityRepository deprecates access to protected variables

Instead of accessing protected variables for the EntityManager in
a custom EntityRepository it is now required to use the getter methods
for all the three instance variables:

* `$this->_em` now accessible through `$this->getEntityManager()`
* `$this->_class` now accessible through `$this->getClassMetadata()`
* `$this->_entityName` now accessible through `$this->getEntityName()`

Important: For Beta 2 the protected visibility of these three properties will be
changed to private!

## Console migrated to Symfony Console

The Doctrine CLI has been replaced by Symfony Console Configuration

Instead of having to specify:

    [php]
    $cliConfig = new CliConfiguration();
    $cliConfig->setAttribute('em', $entityManager);

You now have to configure the script like:

    [php]
    $helperSet = new \Symfony\Components\Console\Helper\HelperSet(array(
        'db' => new \Doctrine\DBAL\Tools\Console\Helper\ConnectionHelper($em->getConnection()),
        'em' => new \Doctrine\ORM\Tools\Console\Helper\EntityManagerHelper($em)
    ));

## Console: No need for Mapping Paths anymore

In previous versions you had to specify the --from and --from-path options
to show where your mapping paths are from the console. However this information
is already known from the Mapping Driver configuration, so the requirement
for this options were dropped.

Instead for each console command all the entities are loaded and to
restrict the operation to one or more sub-groups you can use the --filter flag.

## AnnotationDriver is not a default mapping driver anymore

In conjunction with the recent changes to Console we realized that the
annotations driver being a default metadata driver lead to lots of glue
code in the console components to detect where entities lie and how to load
them for batch updates like SchemaTool and other commands. However the
annotations driver being a default driver does not really help that much
anyways.

Therefore we decided to break backwards compability in this issue and drop
the support for Annotations as Default Driver and require our users to
specify the driver explicitly (which allows us to ask for the path to all
entities).

If you are using the annotations metadata driver as default driver, you
have to add the following lines to your bootstrap code:

    $driverImpl = $config->newDefaultAnnotationDriver(array(__DIR__."/Entities"));
    $config->setMetadataDriverImpl($driverImpl);

You have to specify the path to your entities as either string of a single
path or array of multiple paths
to your entities. This information will be used by all console commands to
access all entities.

Xml and Yaml Drivers work as before!


## New inversedBy attribute

It is now *mandatory* that the owning side of a bidirectional association specifies the
'inversedBy' attribute that points to the name of the field on the inverse side that completes
the association. Example:

    [php]
    // BEFORE (ALPHA4 AND EARLIER)
    class User
    {
        //...
        /** @OneToOne(targetEntity="Address", mappedBy="user") */
        private $address;
        //...
    }
    class Address
    {
        //...
        /** @OneToOne(targetEntity="User") */
        private $user;
        //...
    }
    
    // SINCE BETA1
    // User class DOES NOT CHANGE
    class Address
    {
        //...
        /** @OneToOne(targetEntity="User", inversedBy="address") */
        private $user;
        //...
    }
    
Thus, the inversedBy attribute is the counterpart to the mappedBy attribute. This change
was necessary to enable some simplifications and further performance improvements. We
apologize for the inconvenience.

## Default Property for Field Mappings

The "default" option for database column defaults has been removed. If desired, database column defaults can
be implemented by using the columnDefinition attribute of the @Column annotation (or the approriate XML and YAML equivalents).
Prefer PHP default values, if possible.

## Selecting Partial Objects

Querying for partial objects now has a new syntax. The old syntax to query for partial objects
now has a different meaning. This is best illustrated by an example. If you previously
had a DQL query like this:

    [sql]
    SELECT u.id, u.name FROM User u
    
Since BETA1, simple state field path expressions in the select clause are used to select
object fields as plain scalar values (something that was not possible before).
To achieve the same result as previously (that is, a partial object with only id and name populated)
you need to use the following, explicit syntax:

    [sql]
    SELECT PARTIAL u.{id,name} FROM User u

## XML Mapping Driver

The 'inheritance-type' attribute changed to take last bit of ClassMetadata constant names, i.e.
NONE, SINGLE_TABLE, INHERITANCE_TYPE_JOINED

## YAML Mapping Driver

The way to specify lifecycle callbacks in YAML Mapping driver was changed to allow for multiple callbacks
per event. The Old syntax ways:

    [yaml]
    lifecycleCallbacks:
      doStuffOnPrePersist: prePersist
      doStuffOnPostPersist: postPersist

The new syntax is:

    [yaml]
    lifecycleCallbacks:
      prePersist: [ doStuffOnPrePersist, doOtherStuffOnPrePersistToo ]
      postPersist: [ doStuffOnPostPersist ]

## PreUpdate Event Listeners

Event Listeners listening to the 'preUpdate' event can only affect the primitive values of entity changesets
by using the API on the `PreUpdateEventArgs` instance passed to the preUpdate listener method. Any changes
to the state of the entitys properties won't affect the database UPDATE statement anymore. This gives drastic
performance benefits for the preUpdate event.

## Collection API

The Collection interface in the Common package has been updated with some missing methods
that were present only on the default implementation, ArrayCollection. Custom collection
implementations need to be updated to adhere to the updated interface.