doctrine2/UPGRADE_TO_2_0

## Installing

Currently the only way to install is via svn. So just checkout the trunk.

    $ svn co http://svn.doctrine-project.org/trunk/lib doctrine
    $ cd doctrine

## Loading Doctrine

First we need to require one class, the `ClassLoader`.

>**NOTE**
> This assumes you've created some kind of script to test the following code in. Something like a `test.php` file.

    [php]
    // test.php

    require_once 'lib/Doctrine/Common/ClassLoader.php';

Now we need to instantiate the `ClassLoader` and register it:

    [php]
    $classLoader = new \Doctrine\Common\ClassLoader();
    $classLoader->register();

The Doctrine `ClassLoader` supports the ability to use it for loading other classes with a prefix.

Here are the recommend usages for the Doctrine `ClassLoader`:

* Use only 1 class loader instance.
* Set the base paths to your class libraries (including Doctrine's) through

-

    [php]
    $classLoader->setBasePath($prefix, $basePath);

For example you can set the path for Doctrine with the following:

    [php]
    $classLoader->setBasePath('Doctrine', '/usr/local/phplibs/doctrine/lib');

Then, when trying to load the class Doctrine\ORM\EntityManager, for example the class loader will look for /usr/local/phplibs/doctrine/lib/Doctrine/ORM/EntityManager.php

* DO NOT setCheckFileExists(true). Doing so is expensive in terms of performance.
* Use an opcode-cache (i.e. APC) (STRONGLY RECOMMENDED).

## Initialize Doctrine

    [php]
    $config = new \Doctrine\ORM\Configuration();
    $config->setMetadataCacheImpl(new \Doctrine\ORM\Cache\ArrayCache);
    $eventManager = new \Doctrine\Common\EventManager();
    $connectionOptions = array(
            'user' => 'john',
            'password' => 'wayne'
    );
    $em = \Doctrine\ORM\EntityManager::create($connectionOptions, 'doctrine', $config, $eventManager);

## Getting the Connection

    [php]
    $conn = $em->getConnection();
    $conn->delete('table_name', array(1, 3, 10));

The DBAL Connection class has lots of useful functions. You can browse the code and check the API to get familiar.

## The Schema Manager

The schema manager is a nice API for issuing database DDL statements like creating a table, or dropping a table.

    [php]
    $sm = $connection->getSchemaManager();

The schema manager allows you to do all the familiar options on your schema. Like `createTable()`. Below you will find an example:

    [php]
    $sm->createTable($tableName, $columns, $options);

## The Platform Object

The platform object is the object that provides the appropriate SQL to the schema manager for the DDL statements.

    [php]
    $platform = $connection->getDatabasePlatform();

Now we can get the generated SQL instead of executing it directly:

    [php]
    $sql = $platform->getCreateTableSql($tableName, $columns, $options);