Declare the database table for which this class is defined, using the protected variable $_name. This is a string, and must contain the name of the table spelled as it appears in the database.

<?php

class Bugs extends Zend_Db_Table_Abstract
{
    protected $_name = 'bugs';
}

?>

If you don't specify the table name, it defaults to the name of the class. If you rely on this default, the class name must match the spelling of the table name as it appears in the database.

<?php

class bugs extends Zend_Db_Table_Abstract
{
    // table name matches class name
}

?>

You can also declare the schema for the table in the protected variable $_schema. In some RDBMS brands, the term for this is database or tablespace, but it is used similarly. You can also declare the schema as part of the table string.

<?php

// First alternative:

class Bugs extends Zend_Db_Table_Abstract
{
    protected $_schema = 'bug_db';
    protected $_name = 'bugs';
}

// Second alternative:

class Bugs extends Zend_Db_Table_Abstract
{
    protected $_name = 'bug_db.bugs';
}

?>

If you don't specify the schema name, it defaults to the schema to which your database adapter instance is connected.

Every table should have a primary key. You can declare the column for the primary key using the protected variable $_primary. This is either a string that names the single column for the primary key, or else it is an array of column names if your primary key is a compound key.

<?php

class Bugs extends Zend_Db_Table_Abstract
{
    protected $_name = 'bugs';
    protected $_primary = 'bug_id';
}

?>

If you don't specify the primary key, Zend_Db_Table_Abstract tries to discover the primary key based on the information provided by the describeTable() method.

When you create an instance of a Table class, the constructor calls a set of protected methods that initialize metadata for the table. You can extend any of these methods to define metadata explicitly. Remember to call the parent's method when you are done.

<?php

class Bugs extends Zend_Db_Table_Abstract
{
    protected function _setupTableName()
    {
        $this->_name = 'bugs';
        parent::_setupTableName();
    }
}

?>

The setup methods you can override are the following:

The first way to provide a database adapter to a Table class is by passing it as an object of type Zend_Db_Adapter_Abstract in the options array, identified by the key 'db'.

<?php

$db = Zend_Db::factory('PDO_MYSQL', $options);

$table = new Bugs(array('db' => $db));

?>

The second way to provide a database adapter to a Table class is by declaring an object of type Zend_Db_Adapter_Abstract to be a default database adapter for all subsequent instances of Tables in your application. You can do this with the static method Zend_Db_Table_Abstract::setDefaultAdapter(). The argument is an object of type Zend_Db_Adapter_Abstract.

<?php

$db = Zend_Db::factory('PDO_MYSQL', $options);
Zend_Db_Table_Abstract::setDefaultAdapter($db);

// Later...

$table = new Bugs();

?>

It can be convenient to create the database adapter object in a central place of your application, such as the bootstrap, and then store it as the default adapter. This gives you a means to ensure that the adapter instance is the same throughout your application. However, setting a default adapter is limited to a single adapter instance.

The third way to provide a database adapter to a Table class is by passing a string in the options array, also identified by the 'db' key. The string is used as a key to the static Zend_Registry instance, where the entry at that key is an object of type Zend_Db_Adapter_Abstract.

<?php

$db = Zend_Db::factory('PDO_MYSQL', $options);
Zend_Registry::set('my_db', $db);

// Later...

$table = new Bugs(array('db' => 'my_db'));

?>

Like setting the default adapter, this gives you the means to ensure that the same adapter instance is used throughout your application. Using the registry is more flexible, because you can store more than one adapter instance. A given adapter instance is specific to a certain RDBMS brand and database instance. If your application needs access to multiple databases or even multiple database brands, then you need to use multiple adapters.

An auto-incrementing primary key generates a unique integer value for you if you omit the primary key column from your SQL INSERT statement.

In Zend_Db_Table_Abstract, if you define the protected variable $_sequence to be the Boolean value true, then the class assumes that the table has an auto-incrementing primary key.

<?php

class Bugs extends Zend_Db_Table_Abstract
{
    protected $_name = 'bugs';

    // This is the default in the Zend_Db_Table_Abstract class;
    // you do not need to define this.
    protected $_sequence = true;
}

?>

MySQL, Microsoft SQL Server, and SQLite are examples of RDBMS brands that support auto-incrementing primary keys.

PostgreSQL has a SERIAL notation that implicitly defines a sequence based on the table and column name, and uses the sequence to generate key values for new rows. IBM DB2 has an IDENTITY notation that works similarly. If you use either of these notations, treat your Zend_Db_Table class as having an auto-incrementing column with respect to declaring the $_sequence member as true.

A sequence is a database object that generates a unique value, which can be used as a primary key value in one or more tables of the database.

If you define $_sequence to be a string, then Zend_Db_Table_Abstract assumes the string to name a sequence object in the database. The sequence is invoked to generate a new value, and this value is used in the INSERT operation.

<?php

class Bugs extends Zend_Db_Table_Abstract
{
    protected $_name = 'bugs';

    protected $_sequence = 'bug_sequence';
}

?>

Oracle, PostgreSQL, and IBM DB2 are examples of RDBMS brands that support sequence objects in the database.

PostgreSQL and IBM DB2 also have syntax that defines sequences implicitly and associated with columns. If you use this notation, treat the table as having an auto-incrementing key column. Define the sequence name as a string only in cases where you would invoke the sequence explicitly to get the next key value.

Some tables have a natural key. This means that the key is not automatically generated by the table or by a sequence. You must specify the value for the primary key in this case.

If you define the $_sequence to be the Boolean value false, then Zend_Db_Table_Abstract assumes that the table has a natural primary key. You must provide values for the primary key columns in the array of data to the insert() method, or else this method throws a Zend_Db_Table_Exception.

<?php

class BugStatus extends Zend_Db_Table_Abstract
{
    protected $_name = 'bug_status';

    protected $_sequence = false;
}

?>

	Note
	All RDBMS brands support tables with natural keys. Examples of tables that are often declared as having natural keys are lookup tables, intersection tables in many-to-many relationships, or most tables with compound primary keys.

By default, methods of the Table class return a Rowset in instances of the concrete class Zend_Db_Table_Rowset, and Rowsets contain a collection of instances of the concrete class Zend_Db_Table_Row. You can specify an alternative class to use for either of these, but they must be classes that extend Zend_Db_Table_Rowset_Abstract and Zend_Db_Table_Row_Abstract, respectively.

You can specify Row and Rowset classes using the Table constructor's options array, in keys 'rowClass' and 'rowsetClass' respectively. Specify the names of the classes using strings.

<?php

class My_Row extends Zend_Db_Table_Row_Abstract
{
    ...
}

class My_Rowset extends Zend_Db_Table_Rowset_Abstract
{
    ...
}

$table = new Bugs(
    array(
        'rowClass'    => 'My_Row',
        'rowsetClass' => 'My_Rowset'
    )
);

$where = $table->getAdapter()->quoteInto('bug_status = ?', 'NEW')

// Returns an object of type My_Rowset,
// containing an array of objects of type My_Row.
$rows = $table->fetchAll($where);

?>

You can change the classes by specifying them with the setRowClass() and setRowsetClass() methods. This applies to rows and rowsets created subsequently; it does not change the class of any row or rowset objects you have created previously.

<?php

$table = new Bugs();

$where = $table->getAdapter()->quoteInto('bug_status = ?', 'NEW')

// Returns an object of type Zend_Db_Table_Rowset
// containing an array of objects of type Zend_Db_Table_Row.
$rowsStandard = $table->fetchAll($where);

$table->setRowClass('My_Row');
$table->setRowsetClass('My_Rowset');

// Returns an object of type My_Rowset,
// containing an array of objects of type My_Row.
$rowsCustom = $table->fetchAll($where);

// The $rowsStandard object still exists, and it is unchanged.

?>

For more information on the Row and Rowset classes, see Section 9.5, “Zend_Db_Table_Row” and Section 9.6, “Zend_Db_Table_Rowset”.

You can override the insert() and update() methods in your Table class. This gives you the opportunity to implement custom code that is executed before performing the database operation. Be sure to call the parent class method when you are done.

<?php

class Bugs extends Zend_Db_Table_Abstract
{
    protected $_name = 'bugs';

    public function insert(array $data)
    {
        // add a timestamp
        if (empty($data['created_on'])) {
            $data['created_on'] = time();
        }
        return parent::insert($data);
    }

    public function update(array $data, $where)
    {
        // add a timestamp
        if (empty($data['updated_on'])) {
            $data['updated_on'] = time();
        }
        return parent::update($data, $where);
    }
}

?>

You can also override the delete() method.

You can implement custom query methods in your Table class, if you have frequent need to do queries against this table with specific criteria. Most queries can be written using fetchAll(), but this requires that you duplicate code to form the query conditions if you need to run the query in several places in your application. Therefore it can be convenient to implement a method in the Table class to perform frequently-used queries against this table.

<?php

class Bugs extends Zend_Db_Table_Abstract
{
    protected $_name = 'bugs';

    public function findByStatus($status)
    {
        $where = $this->getAdapter()->quoteInto('bug_status = ?', $status);
        return $this->fetchAll($where, 'bug_id');
    }
}

?>

Some people prefer that the table class name match a table name in the RDBMS by using a string transformation called inflection.

For example, if your table class name is "BugsProducts", it would match the physical table in the database called "bugs_products," if you omit the explicit declaration of the $_name class property. In this inflection mapping, the class name spelled in "CamelCase" format would be transformed to lower case, and words are separated with an underscore.

You can specify the database table name independently from the class name by declaring the table name with the $_name class property in each of your table classes.

Zend_Db_Table_Abstract performs no inflection to map the class name to the table name. If you omit the declaration of $_name in your table class, the class maps to a database table that matches the spelling of the class name exactly.

It is inappropriate to transform identifiers from the database, because this can lead to ambiguity or make some identifiers inaccessible. Using the SQL identifiers exactly as they appear in the database makes Zend_Db_Table_Abstract both simpler and more flexible.

If you prefer to use inflection, then you must implement the transformation yourself, by overriding the _setupTableName() method in your Table classes. One way to do this is to define an abstract class that extends Zend_Db_Table_Abstract, and then the rest of your tables extend your new abstract class.

<?php

abstract class MyAbstractTable extends Zend_Db_Table_Abstract
{
    protected function _setupTableName()
    {
        if (!$this->_name) {
            $this->_name = myCustomInflector(get_class($this));
        }
        parent::_setupTableName();
    }
}

class BugsProducts extends MyAbstractTable
{
}

?>

You are responsible for writing the functions to perform inflection transformation. Zend Framework does not provide such a function.