library/Benri/Auth/Adapter/DbTable.php
public function authenticate()
    {
        $this->_authenticateSetup();

        $dbSelect   = $this->_authenticateCreateSelect();
        $identity   = $this->_authenticateQuerySelect($dbSelect);
        $authResult = $this->_authenticateValidateResultSet($identity);

        if ($authResult instanceof Zend_Auth_Result) {
            return $authResult;
        }

        /// _authenticateValidateResult() attempts to make certain that only
        /// one record was returned in the resultset.
        return $this->_authenticateValidateResult(array_shift($identity));
    }
public function authenticate()
    {
        $this->_authenticateSetup();

        $dbSelect   = $this->_authenticateCreateSelect();
        $identity   = $this->_authenticateQuerySelect($dbSelect);
        $authResult = $this->_authenticateValidateResultSet($identity);

        if ($authResult instanceof Zend_Auth_Result) {
            return $authResult;
        }

        /// _authenticateValidateResult() attempts to make certain that only
        /// one record was returned in the resultset.
        return $this->_authenticateValidateResult(array_shift($identity));
    }
Called to attempt an authentication.

Previous to this call, this adapter would have already been configured
with all necessary information to successfully connect to a database
table and attempt to find a record matching the provided identity.

@return Zend_Auth_Result
@see http://framework.zend.com/manual/1.12/en/zend.auth.introduction.html#zend.auth.introduction.results Zend_Auth_Result
@throws Zend_Auth_Adapter_Exception if answering the authentication
query is impossible