Showing database-errors
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When the database raises an error Cake shows the text 'Please correct the errors below' without telling you what the error is.
This tutorial shows you a way to extend your application to show the user a understandable message after a database error.
This tutorial shows you a way to extend your application to show the user a understandable message after a database error.
Before a start I want to thank ben-xo. His article about detecting duplicate entries provided me the ideas and the basis for this tutorial.
To make your application show database errors you have to:
The tutorial will show the code, and hopefully speaks for itself.
To make your application show database errors you have to:
- Extend your app_model.php.
- Create an element to show database-errors.
- Extend your views with the element.
- Modify your controllers to show the database-errors.
The tutorial will show the code, and hopefully speaks for itself.
xtend your app_model.php.
<?php
/**
* The class AppModel is extended with functions to show meaningfull database-errors.
* The class is able to work with any kind of database.
*
* Put this file in the dir app or the contents of this file in app/app_model.php.
*
* The arrays with error-numbers and messages has to be extended!!
*
*/
class AppModel extends Model{
/**
* Variables to hold information about the raised database-error.
*
*/
var $dbError;
var $dbErrorStr;
var $dbErrorNum;
/**
* User-understandable messages.
* The key is a MySQL number.
* Extend the array with al posible database errors!!
*/
var $dbErrorUserStr = array ( "1062" => 'Record with same key already exists.',
"1217" => 'Record is used in another table.', );
/**
* Mapping between error-numbers and user-understandable messages, per database-type.
* Error numbers for Postgress are FAKE.
* Extend the array with al posible database errors!!
*/
var $dbErrorMapping = array( "DboMysql" => array ( "1062" => '1062',
"1217" => '1217', ),
"DboPostgres" => array ("1111" => '1062',
"8888" => '1217', )
) ;
/**
* Override the function del(),
* Check database-error and call a function to invalidate the form.
*/
function del($id = null, $cascade = true) {
$returnval = parent::del($id , $cascade);
if(false === $returnval) {
$db =& ConnectionManager::getDataSource($this->useDbConfig);
$this->dbError = $db->lastError();
list($this->dbErrorNum, $this->dbErrorStr) = explode(":", $this->dbError);
$this->afterSaveFailed();
}
return $returnval;
}
/**
* Override the function save(),
* Check database-error and call a function to invalidate the form.
*/
function save($data = null, $validate = true, $fieldList = array()) {
$returnval = parent::save($data, $validate, $fieldList);
if(false === $returnval) {
$db =& ConnectionManager::getDataSource($this->useDbConfig);
$this->dbError = $db->lastError();
list($this->dbErrorNum, $this->dbErrorStr) = explode(":", $this->dbError);
$this->afterSaveFailed();
}
return $returnval;
}
/**
* Calls invalidate()
* Maybe overridden in model.
*
*/
function afterSaveFailed() {
$this->invalidate('DbError');
}
/**
* returns the user understandable messages
* if the user understandable message is not defined it returns the originale database-message.
*
*/
function dbErrorUserStr() {
// Determine the type of database...
$db =& ConnectionManager::getDataSource($this->useDbConfig);
$key = get_class($db);
if ($key == 'DboMysqli') $key = 'DboMysql';
// Determine the number of the message using the mapping array.
$dbErrorNum = $this->dbErrorMapping[$key][$this->dbErrorNum];
if ( isset($this->dbErrorUserStr[ $dbErrorNum ])){
return $this->dbErrorUserStr[ $dbErrorNum ];
} else {
return $this->dbError;
}
}
}
?>
Create an element to show database-errors.
<?php
// Suppress the echo if the variable is not defined...
if ( isSet ($dbErrorUserStr)) {
echo $html->tagErrorMsg( $html->model . '/DbError' , $dbErrorUserStr);
}
;?>
Extend your views with the element.
<?php echo $this->renderElement('mainactions'); ?>
<h2>New Speed</h2>
<form action="<?php echo $html->url('/speeds/add'); ?>" method="post">
<div class="optional">
<?php echo $form->labelTag('Speed/id', 'Id');?>
<?php echo $html->input('Speed/id', array('size' => '60'));?>
<?php echo $html->tagErrorMsg('Speed/id', 'Please enter the Id.');?>
</div>
<?php echo $this->renderElement('DbInvalidate'); ?>
<div class="submit">
<?php echo $html->submit('Add');?>
</div>
</form>
Modify your controllers to show the database-errors.
function edit($id = null) {
$this->Speed->recursive = 0;
if(empty($this->data)) {
if(!$id) {
$this->Session->setFlash('Invalid id for Speed');
$this->redirect('/speeds/index');
}
$this->data = $this->Speed->read(null, $id);
} else {
$this->cleanUpFields();
if($this->Speed->save($this->data)) {
$this->Session->setFlash('The Speed has been saved');
$this->redirect('/speeds/index');
} else {
$this->Session->setFlash('Please correct errors below.');
$this->set('dbErrorUserStr', $this->Speed->dbErrorUserStr());
}
}
}
function delete($id = null) {
if(!$id) {
$this->Session->setFlash('Invalid id for Speed');
$this->redirect('/speeds/index');
}
if($this->Speed->del($id)) {
$this->Session->setFlash('The Speed deleted: id '.$id.'');
$this->redirect('/speeds/index');
}
else
{
$this->Session->setFlash( "Record not deleted. " . $this->Speed->dbErrorUserStr() );
$this->redirect($this->referer());
}
}
i am a new user in cakePHP. my data are not saving in database. so to dispaly the database error i have used bellow code
class AppModel extends Model{
/**
* Variables to hold information about the raised database-error.
*
*/
var $dbError;
var $dbErrorStr;
var $dbErrorNum;
/**
* User-understandable messages.
* The key is a MySQL number.
* Extend the array with al posible database errors!!
*/
var $dbErrorUserStr = array ( "1062" => 'Record with same key already exists.',
"1217" => 'Record is used in another table.', );
/**
* Mapping between error-numbers and user-understandable messages, per database-type.
* Error numbers for Postgress are FAKE.
* Extend the array with al posible database errors!!
*/
var $dbErrorMapping = array( "DboMysql" => array ( "1062" => '1062',
"1217" => '1217', ),
"DboPostgres" => array ("1111" => '1062',
"8888" => '1217', )
) ;
/**
* Override the function del(),
* Check database-error and call a function to invalidate the form.
*/
function del($id = null, $cascade = true) {
$returnval = parent::del($id , $cascade);
if(false === $returnval) {
$db =& ConnectionManager::getDataSource($this->useDbConfig);
$this->dbError = $db->lastError();
list($this->dbErrorNum, $this->dbErrorStr) = explode(":", $this->dbError);
$this->afterSaveFailed();
}
return $returnval;
}
/**
* Override the function save(),
* Check database-error and call a function to invalidate the form.
*/
function save($data = null, $validate = true, $fieldList = array()) {
$returnval = parent::save($data, $validate, $fieldList);
if(false === $returnval) {
$db =& ConnectionManager::getDataSource($this->useDbConfig);
$this->dbError = $db->lastError();
print $this->dbError;
list($this->dbErrorNum, $this->dbErrorStr) = explode(":", $this->dbError);
$this->afterSaveFailed();
}
return $returnval;
}
/**
* Calls invalidate()
* Maybe overridden in model.
*
*/
function afterSaveFailed() {
$this->invalidate('DbError');
}
/**
* returns the user understandable messages
* if the user understandable message is not defined it returns the originale database-message.
*
*/
function dbErrorUserStr() {
// Determine the type of database...
$db =& ConnectionManager::getDataSource($this->useDbConfig);
$key = get_class($db);
if ($key == 'DboMysqli') $key = 'DboMysql';
// Determine the number of the message using the mapping array.
$dbErrorNum = $this->dbErrorMapping[$key][$this->dbErrorNum];
if ( isset($this->dbErrorUserStr[ $dbErrorNum ])){
return $this->dbErrorUserStr[ $dbErrorNum ];
} else {
return $this->dbError;
}
}
}
when i try to print $this->dbError, i am getting nothing
Plese help me
Nice tutorial, works great.
I got one suggestion:
To prevent the "headers already sent" error when the $key does not exist, replace:
Model Class:
<?php// Determine the number of the message using the mapping array.
$dbErrorNum = $this->dbErrorMapping[$key][$this->dbErrorNum];
?>
with
Model Class:
<?php// Determine the number of the message using the mapping array.
$dbErrorNum = (isset($this->dbErrorMapping[$key][$this->dbErrorNum]) ? $this->dbErrorMapping[$key][$this->dbErrorNum] : null);
?>
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