MySQL 関数
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.
mysql_affected_rows
(PHP 4, PHP 5)
mysql_affected_rows — 一番最近の操作で変更された行の数を得る
説明
int mysql_affected_rows
([ resource $link_identifier
] )
link_identifier と関連付けられた直近の INSERT、UPDATE、REPLACE、DELETE クエリによって変更された行の数を取得します。
パラメータ
- link_identifier
-
MySQL 接続。 指定されない場合、mysql_connect() により直近にオープンされたリンクが 指定されたと仮定されます。そのようなリンクがない場合、引数を指定せずに mysql_connect() がコールした時と同様にリンクを確立します。 リンクが見付からない、または、確立できない場合、 E_WARNING レベルのエラーが生成されます。
返り値
成功した場合に変更された行の数を、直近のクエリが失敗した場合に -1 を返します。
直近のクエリが WHERE 句を含まない DELETE だった場合、テーブルから すべてのレコードが削除されますが、MySQL 4.1.2 以前のバージョンでは この関数はゼロを返します。
UPDATE を使用する場合、MySQL では新旧の値が同じときには更新処理を行いません。 このことから、必ずしも mysql_affected_rows() の返す値が マッチする行の数と一致するとは限りません。返す値は実際に更新処理が行われた 行の数です。
REPLACE ステートメントは、まず最初に同じ主キーのレコードを削除した後に 新しいレコードを挿入します。この関数は、削除された行の数と 挿入された行の数を足したものを返します。
例
例1 mysql_affected_rows() の例
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');
/* これは、削除されたレコードの正しい数をかえずはず */
mysql_query('DELETE FROM mytable WHERE id < 10');
printf("Records deleted: %d\n", mysql_affected_rows());
/* 決して真にはならない where 条件なので、結果は 0 となるはず */
mysql_query('DELETE FROM mytable WHERE 0');
printf("Records deleted: %d\n", mysql_affected_rows());
?>
上の例の出力は、 たとえば以下のようになります。
Records deleted: 10 Records deleted: 0
例2 トランザクションを利用した mysql_affected_rows() の例
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');
/* レコードの更新 */
mysql_query("UPDATE mytable SET used=1 WHERE id < 10");
printf ("Updated records: %d\n", mysql_affected_rows());
mysql_query("COMMIT");
?>
上の例の出力は、 たとえば以下のようになります。
Updated Records: 10
注意
注意: トランザクション
トランザクションを使用する場合には、コミット後ではなく INSERT, UPDATE, DELETE クエリの後に mysql_affected_rows() をコールする必要があります。
注意: SELECT ステートメント
SELECT から返される行の数を得る際には、 mysql_num_rows() が利用できます。
add a note
User Contributed Notesmysql_affected_rows
sean at adtools dot co dot uk
09-Sep-2008 08:48
09-Sep-2008 08:48
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.