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mysqli->error

mysqli_error

(PHP 5, PHP 7, PHP 8)

mysqli->error -- mysqli_error — Retorna uma string descrevendo o último erro

Descrição

Estilo orientado a objetos

string $mysqli->error;

Estilo procedural

mysqli_error(mysqli $mysql): string

Retorna a última mensagem de erro da chamada de função MySQLi mais recente que possa ter sucesso ou falhar.

Parâmetros

mysql: Somente no estilo procedural: Um objeto mysqli retornado por mysqli_connect() ou mysqli_init()

Valor Retornado

Uma string que descreve o erro. Uma string vazia se não houve erro.

Exemplos

Exemplo #1 Exemplo de $mysqli->error

Estilo orientado a objetos

<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

/* check connection */
if ($mysqli->connect_errno) {
    printf("Connect failed: %s\n", $mysqli->connect_error);
    exit();
}

if (!$mysqli->query("SET a=1")) {
    printf("Error message: %s\n", $mysqli->error);
}

/* close connection */
$mysqli->close();
?>

Estilo procedural

<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

if (!mysqli_query($link, "SET a=1")) {
    printf("Error message: %s\n", mysqli_error($link));
}

/* close connection */
mysqli_close($link);
?>

Os exemplos acima produzirão:

Error message: Unknown system variable 'a'

Veja Também

mysqli_connect_errno() - Retorna o código de erro da última chamada de conexão
mysqli_connect_error() - Retorna uma descrição do último erro de conexão
mysqli_errno() - Retorna o código de erro para a chamada de função mais recente
mysqli_sqlstate() - Retorna o erro SQLSTATE da operação MySQL anterior

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User Contributed Notes 7 notes

down

information at saunderswebsolutions dot com ¶

18 years ago


The mysqli_sql_exception class is not available to PHP 5.05

I used this code to catch errors 
<?php
$query = "SELECT XXname FROM customer_table ";
$res = $mysqli->query($query);

if (!$res) {
   printf("Errormessage: %s\n", $mysqli->error);
}

?>
The problem with this is that valid values for $res are: a mysqli_result object , true or false
This doesn't tell us that there has been an error with the sql used.
If you pass an update statement, false is a valid result if the update fails.

So, a better way is:
<?php
$query = "SELECT XXname FROM customer_table ";
$res = $mysqli->query($query);

if (!$mysqli->error) {
   printf("Errormessage: %s\n", $mysqli->error);
}

?>

This would output something like:
Unexpected PHP error [mysqli::query() [<a href='function.query'>function.query</a>]: (42S22/1054): Unknown column 'XXname' in 'field list'] severity [E_WARNING] in [G:\database.php] line [249]

Very frustrating as I wanted to also catch the sql error and print out the stack trace. 

A better way is:

<?php
mysqli_report(MYSQLI_REPORT_OFF); //Turn off irritating default messages

$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

$query = "SELECT XXname FROM customer_table ";
$res = $mysqli->query($query);

if ($mysqli->error) {
    try {    
        throw new Exception("MySQL error $mysqli->error <br> Query:<br> $query", $msqli->errno);    
    } catch(Exception $e ) {
        echo "Error No: ".$e->getCode(). " - ". $e->getMessage() . "<br >";
        echo nl2br($e->getTraceAsString());
    }
}

//Do stuff with the result
?>
Prints out something like:
Error No: 1054
Unknown column 'XXname' in 'field list'
Query: 
SELECT XXname FROM customer_table

#0 G:\\database.php(251): database->dbError('Unknown column ...', 1054, 'getQuery()', 'SELECT XXname F...')
#1 G:\data\WorkSites\1framework5\tests\dbtest.php(29): database->getString('SELECT XXname F...')
#2 c:\PHP\includes\simpletest\runner.php(58): testOfDB->testGetVal()
#3 c:\PHP\includes\simpletest\runner.php(96): SimpleInvoker->invoke('testGetVal')
#4 c:\PHP\includes\simpletest\runner.php(125): SimpleInvokerDecorator->invoke('testGetVal')
#5 c:\PHP\includes\simpletest\runner.php(183): SimpleErrorTrappingInvoker->invoke('testGetVal')
#6 c:\PHP\includes\simpletest\simple_test.php(90): SimpleRunner->run()
#7 c:\PHP\includes\simpletest\simple_test.php(498): SimpleTestCase->run(Object(HtmlReporter))
#8 c:\PHP\includes\simpletest\simple_test.php(500): GroupTest->run(Object(HtmlReporter))
#9 G:\all_tests.php(16): GroupTest->run(Object(HtmlReporter))

This will actually print out the error, a stack trace and the offending sql statement. Much more helpful when the sql statement is generated somewhere else in the code.

down

se (at) brainbits (dot) net ¶

18 years ago


The decription "mysqli_error -- Returns a string description of the LAST error" is not exactly that what you get from mysqli_error. You get the error description from the last mysqli-function, not from the last mysql-error.

If you have the following situation

if (!$mysqli->query("SET a=1")) {
   $mysqli->query("ROLLBACK;")
   printf("Errormessage: %s\n", $mysqli->error);
}

you don't get an error-message, if the ROLLBACK-Query didn't failed, too. In order to get the right error-message you have to write:

if (!$mysqli->query("SET a=1")) {
   printf("Errormessage: %s\n", $mysqli->error);
   $mysqli->query("ROLLBACK;")
}

down

callforeach at gmail dot com ¶

9 years ago


I had to set mysqli_report(MYSQLI_REPORT_ALL) at the begin of my script to be able to catch mysqli errors within the catch block of my php code.

Initially, I used the below code to throw and subsequent catch mysqli exceptions

<?php
try {
   $mysqli = new mysqli('localhost','root','pwd','db');
    if ($mysqli->connect_errno) 
        throw new Exception($mysqli->connect_error);

} catch (Exception $e) {
     echo $e->getMessage();
}

I realized the exception was being thrown before the actual throw statement and hence the catch block was not being called.

My current code looks like
mysqli_report(MYSQLI_REPORT_ALL) ;
try {
      $mysqli = new mysqli('localhost','root','pwd','db');
      /* I don't need to throw the exception, it's being thrown automatically */

} catch (Exception $e) {
  echo $e->getMessage();
}

This works fine and I'm able to trap all mysqli errors

down

-2

asmith16 at littlesvr dot ca ¶

11 years ago


Please note that the string returned may contain data initially provided by the user, possibly making your code vulnerable to XSS. 

So even if you escape everything in your SQL query using mysqli_real_escape_string(), make sure that if you plan to display the string returned by mysqli_error() you run that string through htmlspecialchars().

As far as I can tell the two escape functions don't escape the same characters, which is why you need both (the first for SQL and the second for HTML/JS).

down

-1

abderrahmanekaddour dot aissat at gmail dot com ¶

2 years ago


<?php

// The idea is the add formated errors information for developers to easier bugs detection.

$myfile = fopen("database_log.log", "r");
$db = new mysqli("localhost", "root","root","data");
if(!$db->query("SELECT")){
  $timestamp = new DateTime();
  $data_err = " {
     \"title\": \" Select statement error \",
     \"date_time\": ".$timestamp->getTimestamp().",
     \"error\":\" ".$db->error." \"
     } "; // Do more information 
  fwrite($myfile, $data_err); // writing data
}
    // In separate file do file read and format it for good visual.

$db->close();  
fclose($myfile);
?>

down

-6

information at saunderswebsolutions dot com ¶

18 years ago


Hi, you can also use the new mysqli_sql_exception to catch sql errors.
Example:
<?php
//set up $mysqli_instance here..
$Select = "SELECT xyz FROM mytable ";
try {
    $res = $mysqli_instance->query($Select);
}catch (mysqli_sql_exception $e) {
    print "Error Code <br>".$e->getCode();
    print "Error Message <br>".$e->getMessage();
    print "Strack Trace <br>".nl2br($e->getTraceAsString());
}

?>
Will print out something like
Error Code: 0
Error Message
No index used in query/prepared statement select sess_value from frame_sessions where sess_name = '5b85upjqkitjsostvs6g9rkul1'
Strack Trace:
#0 G:\classfiles\lib5\database.php(214): mysqli->query('select sess_val...')
#1 G:\classfiles\lib5\Session.php(52): database->getString('select sess_val...')
#2 [internal function]: sess_read('5b85upjqkitjsos...')
#3 G:\classfiles\includes.php(50): session_start()
#4 G:\tests\all_tests.php(4): include('G:\data\WorkSit...')
#5 {main}

down

-7

Anonymous ¶

5 years ago


mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
try {
                $this->connection = mysqli_connect($hostname,$username,$password, $dbname);
} catch (Exception $e) {
                echo "Errno: " . mysqli_connect_errno() . PHP_EOL;
                echo "Text error: " . mysqli_connect_error() . PHP_EOL;
                exit;
}

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