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mysql_affected_rows

(PHP 4, PHP 5)

mysql_affected_rowsObtém o número de linhas atingidas na operação anterior do MySQL

Descrição

int mysql_affected_rows ([ resource $link_identifier ] )

Obtém o número de linhas atingidas pela consulta INSERT, UPDATE, REPLACE ou DELETE mais recente associada ao link_identifier.

Parâmetros

link_identifier

The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() was called with no arguments. If no connection is found or established, an E_WARNING level error is generated.

Valor Retornado

Retona o número de linas atingidas em caso de sucesso, e -1 se a ultima consulta falhou.

Se a ultima consulta foi um consulta DELETE sem a claúsula WHERE, todos os registros terão sido excluídos da tabela mas esta função irá retornar zero com versões do MySQL anteriores a 4.1.2.

Ao usar UPDATE, o MySQL não irá atualizar colunas aonde o novo valor é o mesmo que o valor anterior. Isto cria a possibilidade de que mysql_affected_rows() possa não ser igual ao número de linhas encontradas, apenas o número de linhas que literalmente foram afetadas pela consulta.

O comando REPLACE primeiro exclui o registro com a mesma chave primaria e então insere o novo registro. Esta função retorna o número de registros excluídos mais o número de registros inseridos.

Exemplos

Exemplo #1 Exemplo mysql_affected_rows()

<?php
$link 
mysql_connect('localhost''mysql_user''mysql_password');
if (!
$link) {
    die(
'Não foi possível conectar: ' mysql_error());
}
mysql_select_db('mydb');

/* isto deve retornar o número correto de registros excluídos */
mysql_query('DELETE FROM mytable WHERE id < 10');
printf("Registros excluídos: %d\n"mysql_affected_rows());

/* com uma clausula where que jamais é verdadeira, deve retornar 0 */
mysql_query('DELETE FROM mytable WHERE 0');
printf("Registros Excluídos: %d\n"mysql_affected_rows());
?>

O exemplo acima irá imprimir algo similar à:

Records deleted: 10
Records deleted: 0

Exemplo #2 Exemplo de mysql_affected_rows() usando transações

<?php
$link 
mysql_connect('localhost''mysql_user''mysql_password');
if (!
$link) {
    die(
'Não foi possível conectar: ' mysql_error());
}
mysql_select_db('mydb');

/* Atualiza os registros */
mysql_query("UPDATE mytable SET used=1 WHERE id < 10");
printf ("Registros atualizados: %d\n"mysql_affected_rows());
mysql_query("COMMIT");
?>

O exemplo acima irá imprimir algo similar à:

Updated Records: 10

Notas

Nota: Transações

Se você estiver usando transações, você deve utilizar mysql_affected_rows() depois da sua consulta INSERT, UPDATE, ou DELETE, não depois de COMMIT.

Nota: Comandos SELECT

Para obter o número de linhas retornados por um SELECT, é possível usar mysql_num_rows().

Veja Também

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User Contributed Notes 10 notes

up
7
EToS
7 years ago
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);

   }
?>
up
2
HMax
7 years ago
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.
up
2
sean at adtools dot co dot uk
6 years ago
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.
up
1
temp02 at flexis dot com dot br
9 years ago
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.
up
1
Ome Ko
3 years ago
There are no rows affected by an update with identical data.
So here is one very ugly solution for these cases:
<?
function mysql_matched_rows() {
   $_kaBoom=explode(' ',mysql_info());
   return $_kaBoom[2];
}
?>
up
1
steffen at showsource dot dk
9 years ago
Using OPTIMIZE TABLE will also return true.
So, if you want to check the numbers of deleted records, use mysql_affected_rows() before OPTIMIZE TABLE
up
2
dobrys at abv dot bg
7 years ago
I see that when try to use mysql_affected_rows() with "mysql_pconnect(...)" without link indetifier as param in "mysql_affected_rows()" the result is allways -1.
When use link identifier "mysql_affected_rows($this_sql_connection)" - everything is Fine. This is is on PHP Version 5.2.0
Hope that this was helpfull for somebody
up
0
PaulD
4 years ago
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.
up
-1
cbal at freemail dot hu
2 years ago
I dont know why but sometimes mysql_affected_rows does not work (return 0 or nothing) besides the query worked well.
So use this if you have a problem:

<?php
$result
= mysql_query("update/delete ...");
$last = mysql_query("SELECT ROW_COUNT();");
$last = mysql_fetch_array($last);
?>
up
-1
deponti A_T tiscalinet D0T it
10 years ago
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)
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