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How do you create and use a custom Zend_Db_Adapter?

How do you create and use a custom Zend_Db_Adapter?

Creating and using a custom Zend_Db_Adapter in Zend Framework allows you to extend or modify database functionality to suit your needs. Here’s how you can create and use a custom Zend_Db_Adapter:

1. Create the Custom Adapter Class

You need to create a new class that extends Zend_Db_Adapter_Abstract or one of the existing adapters like Zend_Db_Adapter_Pdo_Mysql, depending on your requirements.

Example

<?php
class My_Custom_Db_Adapter extends Zend_Db_Adapter_Pdo_Mysql
{
    // Override or extend any methods here
    
    // Example: Custom query logging
    public function query($sql, $bind = array())
    {
        // Log the query (or do anything custom)
        error_log("Executing query: " . $sql);
        
        // Call parent method to keep the default behavior
        return parent::query($sql, $bind);
    }
}

?>

In this example, the custom adapter extends the MySQL adapter (Zend_Db_Adapter_Pdo_Mysql) and overrides the query() method to log queries.

2. Register Your Custom Adapter

To use this custom adapter in your application, you need to register it with Zend Framework. You can do this in your application.ini configuration file or during runtime.

Option 1: Using application.ini You can specify the adapter class directly in your application.ini configuration:

Example

<?php
resources.db.adapter = "My_Custom_Db_Adapter"
resources.db.params.host = "localhost"
resources.db.params.username = "root"
resources.db.params.password = "password"
resources.db.params.dbname = "my_database"
?>

Option 2: During Runtime Alternatively, you can instantiate the custom adapter programmatically:

Example

<?php
// Use custom adapter during runtime
$config = array(
    'host'     => 'localhost',
    'username' => 'root',
    'password' => 'password',
    'dbname'   => 'my_database',
);

$dbAdapter = new My_Custom_Db_Adapter($config);
?>
3. Use the Custom Adapter

Once the adapter is registered, you can use it as you would any Zend_Db_Adapter. For example:

Example

<?php
// Perform a query using the custom adapter
$dbAdapter->query('SELECT * FROM users');
?>

If you’re using Zend’s resources management, you can retrieve the adapter from the bootstrap:

Example

<?php
$dbAdapter = Zend_Registry::get('db');
?>
4. Extending Functionality

You can customize your adapter to fit your needs, such as:

  • Query logging
  • Custom connection handling
  • Adding profiling or caching layers
  • Handling specific database behavior
Example: Custom Adapter with Connection Pooling

You could add functionality like connection pooling or load balancing by modifying how the adapter connects to the database:

Example

<?php
class My_Custom_Db_Adapter extends Zend_Db_Adapter_Pdo_Mysql
{
    protected $_pool = array();

    public function getConnection()
    {
        if (empty($this->_pool)) {
            // Initialize a new connection pool
            for ($i = 0; $i < 5; $i++) {
                $this->_pool[] = parent::getConnection();
            }
        }

        // Return a connection from the pool
        return array_pop($this->_pool);
    }

    public function closeConnection()
    {
        // Return the connection back to the pool
        $this->_pool[] = $this->_connection;
        $this->_connection = null;
    }
}
?>

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