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mysqli::$error

mysqli_error

(PHP 5)

mysqli::$error -- mysqli_errorReturns a string description of the last error

Beschreibung

Objektorientierter Stil

Prozeduraler Stil

string mysqli_error ( mysqli $link )

Returns the last error message for the most recent MySQLi function call that can succeed or fail.

Parameter-Liste

link

Nur bei prozeduralem Aufruf: Ein von mysqli_connect() oder mysqli_init() zur├╝ckgegebenes Verbindungsobjekt.

R├╝ckgabewerte

A string that describes the error. An empty string if no error occurred.

Beispiele

Beispiel #1 $mysqli->error example

Objektorientierter Stil

<?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("Errormessage: %s\n"$mysqli->error);
}

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

Prozeduraler Stil

<?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("Errormessage: %s\n"mysqli_error($link));
}

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

Die obigen Bespiele erzeugen folgende Ausgabe:

Errormessage: Unknown system variable 'a'

Siehe auch

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User Contributed Notes 5 notes

up
8
information at saunderswebsolutions dot com
8 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.
up
2
information at saunderswebsolutions dot com
8 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}
up
0
asmith16 at littlesvr dot ca
8 months 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).
up
0
se (at) brainbits (dot) net
8 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;")
}
up
-1
jlarsen at fsu dot edu
4 years ago
try/catch on $mysqli->query
doesn't catch most SQL errors, you should use $mysqli->error
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