Doctrine_manual-1-2-en

Chapter 20: Database

Chapter 20: Database Abstraction Layer 292 Chapter 20 Database Abstraction Layer The Doctrine Database Abstraction Layer is the underlying framework that the ORM uses to communicate with the database and send the appropriate SQL depending on which database type you are using. It also has the ability to query the database for information like what table a database has or what fields a table has. This is how Doctrine is able to generate your models from existing databases so easily. This layer can be used independently of the ORM. This might be of use for example if you have an existing application that uses PDO directly and you want to port it to use the Doctrine Connections and DBAL. At a later phase you could begin to use the ORM for new things and rewrite old pieces to use the ORM. The DBAL is composed of a few different modules. In this chapter we will discuss the different modules and what their jobs are. Export The Export module provides methods for managing database structure. The methods can be grouped based on their responsibility: create, edit (alter or update), list or delete (drop) database elements. The following document lists the available methods, providing examples of their use. Introduction Every schema altering method in the Export module has an equivalent which returns the SQL that is used for the altering operation. For example createTable() executes the query / queries returned by createTableSql(). In this chapter the following tables will be created, altered and finally dropped, in a database named events_db: events Name Type Primary Auto Increment id integer true true name string(255) false false datetime timestamp false false people Name Type Primary Auto Increment ----------------- Brought to you by

Chapter 20: Database Abstraction Layer 293 id integer true true name string(255) false false event_participants Name Type Primary Auto Increment event_id integer true false person_id string(255) true false Creating Databases It is simple to create new databases with Doctrine. It is only a matter of calling the createDatabase() function with an argument that is the name of the database to create. // test.php Listing 20-1 // ... $conn->export->createDatabase('events_db'); Now lets change the connection in our bootstrap.php file to connect to the new events_db: // bootstrap.php Listing 20-2 /** * Bootstrap Doctrine.php, register autoloader and specify * configuration attributes */ // ... $conn = Doctrine_Manager::connection('mysql://root:@localhost/events_db', 'doctrine'); // ... Creating Tables Now that the database is created and we've re-configured our connection, we can proceed with adding some tables. The method createTable() takes three parameters: the table name, an array of field definition and some extra options (optional and RDBMS-specific). Now lets create the events table: // test.php Listing 20-3 // $definition = array( 'id' => array( 'type' => 'integer', 'primary' => true, 'autoincrement' => true ), 'name' => array( 'type' => 'string', 'length' => 255 ----------------- Brought to you by