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mysql_affected_rows

(PHP 4, PHP 5)

mysql_affected_rows — Get number of affected rows in previous MySQL operation

Avviso

Questa enstensione deprecata da PHP 5.5.0, e sarà rimossa in futuro. Al suo posto, usare l'estensione MySQLi o PDO_MySQL. Vedere anche la guida MySQL: scelta dell'API e le FAQ relative per ulteriori informazioni. Le alternative a questa funzione includono:

Descrizione

mysql_affected_rows(resource $link_identifier = NULL): int

Get the number of affected rows by the last INSERT, UPDATE, REPLACE or DELETE query associated with link_identifier.

Elenco dei parametri

link_identifier

La connessione MySQL. Se l'identificativo di connessione non è specificato, l'ultima connessione aperta da mysql_connect() viene assunta. Se questa connessione non è trovata, si cercherà di crearne una come se mysql_connect() fosse stata chiamata senza argomenti. Se una connessione non è trovata oppure non viene stabilita, un avviso di livello E_WARNING viene generato.

Valori restituiti

Returns the number of affected rows on success, and -1 if the last query failed.

If the last query was a DELETE query with no WHERE clause, all of the records will have been deleted from the table but this function will return zero with MySQL versions prior to 4.1.2.

When using UPDATE, MySQL will not update columns where the new value is the same as the old value. This creates the possibility that mysql_affected_rows() may not actually equal the number of rows matched, only the number of rows that were literally affected by the query.

The REPLACE statement first deletes the record with the same primary key and then inserts the new record. This function returns the number of deleted records plus the number of inserted records.

In the case of "INSERT ... ON DUPLICATE KEY UPDATE" queries, the return value will be 1 if an insert was performed, or 2 for an update of an existing row.

Esempi

Example #1 mysql_affected_rows() example

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');

/* this should return the correct numbers of deleted records */
mysql_query('DELETE FROM mytable WHERE id < 10');
printf("Records deleted: %d\n", mysql_affected_rows());

/* with a where clause that is never true, it should return 0 */
mysql_query('DELETE FROM mytable WHERE 0');
printf("Records deleted: %d\n", mysql_affected_rows());
?>

Il precedente esempio visualizzerà qualcosa simile a:

Records deleted: 10
Records deleted: 0

Example #2 mysql_affected_rows() example using transactions

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');

/* Update records */
mysql_query("UPDATE mytable SET used=1 WHERE id < 10");
printf ("Updated records: %d\n", mysql_affected_rows());
mysql_query("COMMIT");
?>

Il precedente esempio visualizzerà qualcosa simile a:

Updated Records: 10

Note

Nota: Transactions
If you are using transactions, you need to call mysql_affected_rows() after your INSERT, UPDATE, or DELETE query, not after the COMMIT.

Nota: SELECT Statements
To retrieve the number of rows returned by a SELECT, it is possible to use mysql_num_rows().

Nota: Cascaded Foreign Keys
mysql_affected_rows() does not count rows affected implicitly through the use of ON DELETE CASCADE and/or ON UPDATE CASCADE in foreign key constraints.

Vedere anche: