CustomAbstractDB.php

<?php
/**
 * Zend Framework (http://framework.zend.com/)
 *
 * @link      http://github.com/zendframework/zf2 for the canonical source repository
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd New BSD License
 * @package   Zend_Validator
 */

namespace Zend\Validator\Db;

use Traversable;
use Zend\Db\Adapter\Adapter as DbAdapter;
use Zend\Db\Adapter\Driver\DriverInterface as DbDriverInterface;
use Zend\Db\Sql\Select as DbSelect;
use Zend\Db\Sql\TableIdentifier;
use Zend\Stdlib\ArrayUtils;
use Zend\Validator\AbstractValidator;
use Zend\Validator\Exception;

/**
 * Class for Database record validation
 *
 * @category   Zend
 * @package    Zend_Validate
 */
abstract class CustomAbstractDb extends AbstractValidator
{
    /**
     * Error constants
     */
    const ERROR_NO_RECORD_FOUND = 'noRecordFound';
    const ERROR_RECORD_FOUND    = 'recordFound';

    /**
     * @var array Message templates
     */
    protected $messageTemplates = array(
        self::ERROR_NO_RECORD_FOUND => "No record matching the input was found",
        self::ERROR_RECORD_FOUND    => "A record matching the input was found",
    );

    /**
     * Select object to use. can be set, or will be auto-generated
     *
     * @var DbSelect
     */
    protected $select;

    /**
     * @var string
     */
    protected $schema = null;

    /**
     * @var string
     */
    protected $table = '';

    /**
     * @var string
     */
    protected $field = '';

    /**
     * @var mixed
     */
    protected $exclude = null;

    /**
     * @var mixed
     */
    protected $include = null;

    /**
     * Database adapter to use. If null isValid() will throw an exception
     *
     * @var \Zend\Db\Adapter\Adapter
     */
    protected $adapter = null;

    /**
     * Provides basic configuration for use with Zend\Validator\Db Validators
     * Setting $exclude allows a single record to be excluded from matching.
     * Exclude can either be a String containing a where clause, or an array with `field` and `value` keys
     * to define the where clause added to the sql.
     * A database adapter may optionally be supplied to avoid using the registered default adapter.
     *
     * The following option keys are supported:
     * 'table'   => The database table to validate against
     * 'schema'  => The schema keys
     * 'field'   => The field to check for a match
     * 'exclude' => An optional where clause or field/value pair to exclude from the query
     * 'adapter' => An optional database adapter to use
     *
     * @param array|Traversable|DbSelect $options Options to use for this validator
     * @throws \Zend\Validator\Exception\InvalidArgumentException
     */
    public function __construct($options = null)
    {
        parent::__construct();

        if ($options instanceof DbSelect) {
            $this->setSelect($options);
            return;
        }

        if ($options instanceof Traversable) {
            $options = ArrayUtils::iteratorToArray($options);
        } elseif (func_num_args() > 1) {
            $options       = func_get_args();
            $firstArgument = array_shift($options);
            if (is_array($firstArgument)) {
                $temp = ArrayUtils::iteratorToArray($firstArgument);
            } else {
                $temp['table'] = $firstArgument;
            }

            $temp['field'] = array_shift($options);

            if (!empty($options)) {
                $temp['exclude'] = array_shift($options);
            }

            if (!empty($options)) {
                $temp['include'] = array_shift($options);
            }

            if (!empty($options)) {
                $temp['adapter'] = array_shift($options);
            }

            $options = $temp;
        }

        if (!array_key_exists('table', $options) && !array_key_exists('schema', $options)) {
            throw new Exception\InvalidArgumentException('Table or Schema option missing!');
        }

        if (!array_key_exists('field', $options)) {
            throw new Exception\InvalidArgumentException('Field option missing!');
        }

        if (array_key_exists('adapter', $options)) {
            $this->setAdapter($options['adapter']);
        }

        if (array_key_exists('exclude', $options)) {
            $this->setExclude($options['exclude']);
        }

        if (array_key_exists('include', $options)) {
            $this->setInclude($options['include']);
        }

        $this->setField($options['field']);
        if (array_key_exists('table', $options)) {
            $this->setTable($options['table']);
        }

        if (array_key_exists('schema', $options)) {
            $this->setSchema($options['schema']);
        }
    }

    /**
     * Returns the set adapter
     *
     * @throws \Zend\Validator\Exception\RuntimeException When no database adapter is defined
     * @return DbAdapter
     */
    public function getAdapter()
    {
        return $this->adapter;
    }

    /**
     * Sets a new database adapter
     *
     * @param  DbAdapter $adapter
     * @return self Provides a fluent interface
     */
    public function setAdapter(DbAdapter $adapter)
    {
        $this->adapter = $adapter;
        return $this;
    }

    /**
     * Returns the set exclude clause
     *
     * @return string|array
     */
    public function getExclude()
    {
        return $this->exclude;
    }

    /**
     * Returns the set include clause
     *
     * @return string|array
     */
    public function getInclude()
    {
        return $this->include;
    }


    /**
     * Sets a new exclude clause
     *
     * @param string|array $exclude
     * @return self Provides a fluent interface
     */
    public function setExclude($exclude)
    {
        $this->exclude = $exclude;
        return $this;
    }


    /**
     * Sets a new include clause
     *
     * @param string|array $include
     * @return self Provides a fluent interface
     */
    public function setInclude($include)
    {
        $this->include = $include;
        return $this;
    }


    /**
     * Returns the set field
     *
     * @return string|array
     */
    public function getField()
    {
        return $this->field;
    }

    /**
     * Sets a new field
     *
     * @param string $field
     * @return AbstractDb
     */
    public function setField($field)
    {
        $this->field = (string)$field;
        return $this;
    }

    /**
     * Returns the set table
     *
     * @return string
     */
    public function getTable()
    {
        return $this->table;
    }

    /**
     * Sets a new table
     *
     * @param string $table
     * @return self Provides a fluent interface
     */
    public function setTable($table)
    {
        $this->table = (string)$table;
        return $this;
    }

    /**
     * Returns the set schema
     *
     * @return string
     */
    public function getSchema()
    {
        return $this->schema;
    }

    /**
     * Sets a new schema
     *
     * @param string $schema
     * @return self Provides a fluent interface
     */
    public function setSchema($schema)
    {
        $this->schema = $schema;
        return $this;
    }

    /**
     * Sets the select object to be used by the validator
     *
     * @param  DbSelect $select
     * @return self Provides a fluent interface
     */
    public function setSelect(DbSelect $select)
    {
        $this->select = $select;
        return $this;
    }

    /**
     * Gets the select object to be used by the validator.
     * If no select object was supplied to the constructor,
     * then it will auto-generate one from the given table,
     * schema, field, and adapter options.
     *
     * @return DbSelect The Select object which will be used
     */
    public function getSelect()
    {
        if ($this->select instanceof DbSelect) {
            return $this->select;
        }

        $adapter  = $this->getAdapter();
        $driver   = $adapter->getDriver();
        $platform = $adapter->getPlatform();

        /*
         * Build select object
         */
        $select          = new DbSelect();
        $tableIdentifier = new TableIdentifier($this->table, $this->schema);
        $select->from($tableIdentifier)->columns(
            array($this->field)
        );

        // Support both named and positional parameters
        if (DbDriverInterface::PARAMETERIZATION_NAMED == $driver->getPrepareType()) {
            $select->where(
                $platform->quoteIdentifier($this->field, true) . ' = :value'
            );
        } else {
            $select->where(
                $platform->quoteIdentifier($this->field, true) . ' = ?'
            );
        }

        if ($this->exclude !== null) {
            if (is_array($this->exclude)) {
                $select->where->notEqualTo(
                    $this->exclude['field'],
                    $this->exclude['value']
                );
            } else {
                $select->where($this->exclude);
            }
        }

        if ($this->include !== null) {
            if (is_array($this->include)) {
                $select->where->equalTo(
                    $this->include['field'],
                    $this->include['value']
                );
            } else {
                $select->where($this->include);
            }
        }


        $this->select = $select;

        return $this->select;
    }

    /**
     * Run query and returns matches, or null if no matches are found.
     *
     * @param  string $value
     * @return array when matches are found.
     */
    protected function query($value)
    {
        $adapter  = $this->getAdapter();
        $statement = $adapter->createStatement();
        $this->getSelect()->prepareStatement($adapter, $statement);

        return $statement->execute(array('value' => $value))->current();
    }
}

CustomNoRecordExists.php

<?php
/**
 * Zend Framework (http://framework.zend.com/)
 *
 * @link      http://github.com/zendframework/zf2 for the canonical source repository
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd New BSD License
 * @package   Zend_Validator
 */

namespace Zend\Validator\Db;

use Zend\Validator\Exception;

/**
 * Confirms a record does not exist in a table.
 *
 * @category   Zend
 * @package    Zend_Validate
 */
class CustomNoRecordExists extends CustomAbstractDb
{
    public function isValid($value)
    {
        /*
         * Check for an adapter being defined. If not, throw an exception.
         */
        if (null === $this->adapter) {
            throw new Exception\RuntimeException('No database adapter present');
        }

        $valid = true;
        $this->setValue($value);

        $result = $this->query($value);
        if ($result) {
            $valid = false;
            $this->error(self::ERROR_RECORD_FOUND);
        }

        return $valid;
    }
}

myController.php

<?php 
//Check no other users have the username
$user_id   = $user->getId();
$validator = new Zend\Validator\Db\CustomNoRecordExists(
    array(
        'table' => 'users',
        'field' => 'username',
        'include' => array(
            'field' => 'id',
            'value' => $user_id
        )
    )
);

if ($validator->isValid($username)) {
    // username appears to be valid
} else {
    // username is invalid; print the reason
    $messages = $validator->getMessages();
    foreach ($messages as $message) {
        echo "$message\n";
    }
}

?>