Fonctions MySQL
Just a note: [you should] check for a mysql_affected_rows() return value of -1. If a series of queries were run as a transaction and one query failed, the logic in the foreach loop of the transaction() method in class MySQLDB will not issue a ROLLBACK. It may also be slightly more efficient to stop processing queries on the first failure.
mysql_affected_rows
(PHP 4, PHP 5)
mysql_affected_rows — Retourne le nombre de lignes affectées lors de la dernière opération MySQL
Description
int mysql_affected_rows
([ resource $link_identifier
] )
Retourne le nombre de lignes affectées lors de la dernière requête INSERT, UPDATE, REPLACE ou DELETE avec link_identifier .
Liste de paramètres
- link_identifier
-
La connexion MySQL. S'il n'est pas spécifié, la dernière connexion ouverte avec la fonction mysql_connect() sera utilisée. Si une telle connexion n'est pas trouvée, la fonction tentera d'ouvrir une connexion, comme si la fonction mysql_connect() avait été appelée sans argument. Si aucune connexion n'est trouvée ou établie, une alerte E_WARNING est générée.
Valeurs de retour
Retourne le nombre de lignes affectées en cas de succès et -1 si la dernière requête a échoué.
Si la dernière requête était un DELETE sans clause WHERE, tous les enregistrements ont été effacés, mais cette fonction va retourner 0 avec les versions de MySQL antérieures à 4.1.2.
Lorsque vous utilisez UPDATE, MySQL ne mettra pas à jour les colonnes si la nouvelle valeur est identique à l'ancienne. Il est donc possible que mysql_affected_rows() ne représente pas forcément le nombre de lignes correspondantes mais plutôt le nombre de lignes qui ont été réellement affectées par la requête.
La requête REPLACE commence par effacer les enregistrements possédant la même clé primaire et ensuite, insert les nouveaux enregistrements. Cette fonction retourne le nombre d'enregistrements effacés ainsi que le nombre d'enregistrements insérés.
Exemples
Exemple #1 Exemple avec mysql_affected_rows()
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Impossible de se connecter : ' . mysql_error());
}
mysql_select_db('mydb');
/* Ceci devrait retourner le nombre correct de lignes effacées */
mysql_query('DELETE FROM mytable WHERE id < 10');
printf("Lignes effacées : %d\n", mysql_affected_rows());
/* avec la clause where qui n'est jamais vraie, on devrait obtenir 0 */
mysql_query('DELETE FROM mytable WHERE 0');
printf("Lignes effacées : %d\n", mysql_affected_rows());
?>
L'exemple ci-dessus va afficher quelque chose de similaire à :
Lignes effacées : 10 Lignes effacées : 0
Exemple #2 Exemple avec mysql_affected_rows() en utilisant les transactions
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Impossible de se connecter : ' . mysql_error());
}
mysql_select_db('mydb');
/* Mise à jour des lignes */
mysql_query("UPDATE mytable SET used=1 WHERE id < 10");
printf ("Lignes modifiées : %d\n", mysql_affected_rows());
mysql_query("COMMIT");
?>
L'exemple ci-dessus va afficher quelque chose de similaire à :
Lignes modifiées : 10
Notes
Note: Transactions
Si vous utilisez des transactions, vous devez appeler mysql_affected_rows() après votre requête INSERT, UPDATE ou DELETE et non après le COMMIT.
Note: Requêtes SELECT
Pour obtenir le nombre de lignes retournées par un SELECT, il est possible d'utiliser mysql_num_rows().
Voir aussi
- mysql_num_rows() - Retourne le nombre de lignes d'un résultat MySQL
- mysql_info() - Lit des informations à propos de la dernière requête MySQL
add a note
User Contributed Notesmysql_affected_rows
PaulD
08-Nov-2009 04:35
08-Nov-2009 04:35
sean at adtools dot co dot uk
09-Sep-2008 08:48
09-Sep-2008 08:48
Here's a little function I've been using for a while now, pass it two parameters (action command (1 or 0 see notes)) and a sql statement.
It returns a simple line which shows the length of time taken to action the query, the status of the query (0= query not actioned, you can set this value for testing, 1=success qry executed successfully, -1= failed, there was a problem with the sql statement) the number of lines affected by that query and the sql statement itself.
I've found this invaluable when trying to tie down large amounts of updates to a table, using this you can easily see where a query was successfully executed and the number of rows are affected, or where there are problems and a statement has failed for example.
<?php
function dosql($action,$sql){
# assuming you have setup a link to your database entitled $link
# action = 1 run this query
# action = 0 don't run, just return sql statement
$start = getmtime();
if($action==1){
$result = mysql_query($sql);
$affectedrows = "[".mysql_affected_rows($link)."]";
}
return "[".number_format((getmtime()-$start),3)."][$action]: $sql\n";
mysql_free_result($result);
}
?>
Example output:
[0.072][1][80]: UPDATE MYTABLE SET FIELD = 1;
[0.106][1][758]: UPDATE ANOTHERTABLE SET FIELD = 2;
[0.006][-1][0]: UPDATER ANOTHERTABLE SET FIELD = 2;
The output shows:
[Timetaken][result]][lines affected]
The result will be either -1, 0 or 1, -1 means there's a problem with the sql statement, 1 means it executed correctly, 0 means it wasn't executed.
EToS
09-Aug-2007 08:57
09-Aug-2007 08:57
i found a pretty nice way, this db class/function will accept an array of arrays of querys, it will auto check every line for affected rows in db, if one is 0 it will rollback and return false, else it will commit and return true, the call to the function is simple and is easy to read etc
----------
<?php
class MySQLDB
{
private $connection; // The MySQL database connection
/* Class constructor */
function MySQLDB(){
/* Make connection to database */
$this->connection = mysql_connect(DB_SERVER, DB_USER, DB_PASS) or die(mysql_error());
mysql_select_db(DB_NAME, $this->connection) or die(mysql_error());
}
/* Transactions functions */
function begin(){
$null = mysql_query("START TRANSACTION", $this->connection);
return mysql_query("BEGIN", $this->connection);
}
function commit(){
return mysql_query("COMMIT", $this->connection);
}
function rollback(){
return mysql_query("ROLLBACK", $this->connection);
}
function transaction($q_array){
$retval = 1;
$this->begin();
foreach($q_array as $qa){
$result = mysql_query($qa['query'], $this->connection);
if(mysql_affected_rows() == 0){ $retval = 0; }
}
if($retval == 0){
$this->rollback();
return false;
}else{
$this->commit();
return true;
}
}
};
/* Create database connection object */
$database = new MySQLDB;
// then from anywhere else simply put the transaction queries in an array or arrays like this:
function function(){
global $database;
$q = array (
array("query" => "UPDATE table WHERE something = 'something'"),
array("query" => "UPDATE table WHERE something_else = 'something_else'"),
array("query" => "DELETE FROM table WHERE something_else2 = 'something_else2'"),
);
$database->transaction($q);
}
?>
HMax
02-Jul-2007 10:21
02-Jul-2007 10:21
If you use "INSERT INTO ... ON DUPLICATE KEY UPDATE" syntax, mysql_affected_rows() will return you 2 if the UPDATE was made (just as it does with the "REPLACE INTO" syntax) and 1 if the INSERT was.
So if you use one SQL request to insert several rows at a time, and some are inserted, some are just updated, you won't get the real count.
dobrys at abv dot bg
28-May-2007 09:35
28-May-2007 09:35
I see that when try to use mysql_affected_rows() with "mysql_pconnect(...)" without link indetifier as param in "mysql_affected_rows()" the result is allways -1.
When use link identifier "mysql_affected_rows($this_sql_connection)" - everything is Fine. This is is on PHP Version 5.2.0
Hope that this was helpfull for somebody
Typer85 at gmail dot com
31-Dec-2006 04:35
31-Dec-2006 04:35
Just to clarify about the possible return values in this Manual those not familiar with PHP and MySQL.
"-1 indicates that the query returned an error."
-1 will be returned if the query itself can not be issued to the server, possibly because of syntax error AND if the last query was not either an Insert or Update statement.
mlugassy at 2find dot co dot il
08-Oct-2005 01:22
08-Oct-2005 01:22
To solve the affectedRows() issue on MySQL using PEAR::DB, simply add a 'client_flags' key with a value of 2 to your $dsn options:
<?php
$dsn = array(
'phptype' => 'mysql',
'client_flags' => 2,
'username' => 'someuser',
'password' => 'apasswd',
'hostspec' => 'localhost',
'database' => 'thedb',
);
?>
temp02 at flexis dot com dot br
29-Jun-2005 12:39
29-Jun-2005 12:39
SCENARIO
1. You're using MySQL 4.1x with foreign keys.
2. You have table t2 linked to table t1 by a CASCADE ON DELETE foreign key.
3. t2 has a UNIQUE key so that duplicate records are unacceptable.
3. You have a REPLACE query on t1 followed by an INSERT query on t2 and expect the second query to fail if there's an attempted insert of a duplicate record.
PROBLEM
You notice that the second query is not failing as you had expected even though the record being inserted is an exact duplicate of a record previously inserted.
CAUSE
When the first query (the REPLACE query) deletes a record from t1 in the first stage of the REPLACE operation, it cascades the delete to the record that would be duplicated in t2. The second query then does not fail because the "duplicate" record is no longer a duplicate, as the original one has just been deleted.
steffen at showsource dot dk
28-Sep-2004 10:20
28-Sep-2004 10:20
Using OPTIMIZE TABLE will also return true.
So, if you want to check the numbers of deleted records, use mysql_affected_rows() before OPTIMIZE TABLE
deponti A_T tiscalinet D0T it
07-Nov-2003 12:52
07-Nov-2003 12:52
It works also for REPLACE query,returning:
0 if the record it's already updated (0 record modified),
1 if the record it's new (1 record inserted),
2 if the record it's updated (2 operations: 1 deletion+ 1 insertion)
ben-xo at NOSPAMdubplatesNOSPAM dot org
21-Apr-2002 02:30
21-Apr-2002 02:30
mysql_affected_rows() reports on the number of rows affected by an in-place operation on the database, but mysql_num_rows() returns the number of rows in a MySQL record set (which is held by PHP after MySQL has generated it). This means that if you can do
<?php
$a = mysql_query("SELECT ...");
$b = mysql_query("SELECT ...");
if (mysql_unm_rows($a) > mysql_num_rows($b)) print "a is larger";
else print "b is larger";
?>
... but this does not make sense for the operations supported by mysql_affected_rows(), which reports on the status of the database connection as a whole.
Particularly note this:
<?php
$query = "UPDATE ...";
mysql_query($query);
print mysql_affected_rows(); // more than 0
mysql_query($query); // same query twice
print mysql_affected_rows(); // 0.
?>
.. this is because the 2nd time you execute the identical query, all the rows are already updated so no rows are affected the 2nd time.
I hope this clears up why mysql_num_rows() and mysql_affected_rows() are fundamentally different
dfylstra at frontsys dot com
13-Aug-2001 07:06
13-Aug-2001 07:06
mysql_affected_rows() also reports the number of rows changed by the LOAD DATA command. If you use the IGNORE option in LOAD DATA and you know the number of rows in the input file, you can use mysql_affected_rows() to determine the number of rows that were ignored.