MySQL 関数
I liked the idea of using transactions as written by EToS, however the table/database must support transactions.
I tried this on a MyISAM table, which didn't yield any errors, but just inserted my query.
Works great on InnoDB tables.
mysql_affected_rows
(PHP 4, PHP 5, PECL mysql:1.0)
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
root at it dot dk
11-Apr-2008 06:06
11-Apr-2008 06:06
EToS
09-Aug-2007 10:57
09-Aug-2007 10:57
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
----------
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 12:21
02-Jul-2007 12:21
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 11:35
28-May-2007 11:35
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
mlugassy at 2find dot co dot il
08-Oct-2005 03:22
08-Oct-2005 03:22
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:
$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 02:39
29-Jun-2005 02:39
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.
jeroen_vde at hotmail dot com
12-Mar-2005 02:22
12-Mar-2005 02:22
If you want to delete all in table, and get number of affected rows back use a delete statment of this form:
mysql> DELETE FROM table_name WHERE 1>0;
Note that this is much slower than DELETE FROM table_name with no WHERE clause, because it deletes rows one at a time.
Source: MySQL Reference Manual "Delete Syntax"
steffen at showsource dot dk
28-Sep-2004 12:20
28-Sep-2004 12:20
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
sam_dot_fullman_at_verizon.nt
19-May-2004 09:12
19-May-2004 09:12
Just a MySQL note, using REPLACE INTO on a record could return either ONE or TWO affected rows with this function. Basically, REPLACE INTO will insert a record if no combination of unique keys is matched, or delete the existing record if the new record matches one or more unique keys, then insert the new record over it.
This is actually helpful if you want to know if a record was already in there. (Affected rows=1 means there wasn't already a record there, Affected rows=2 means there was), but if you don't know how REPLACE INTO works it could confuse you. I didn't see this in the notes above and hope it helps someone out.
deponti A_T tiscalinet D0T it
07-Nov-2003 01:52
07-Nov-2003 01:52
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)
Richard dot Johnson2 at student dot gu dot edu dot au
25-Oct-2003 12:56
25-Oct-2003 12:56
RE: sng2nara's comment
I think the expression should read:
"/^[^0-9]+([0-9]+)[^0-9]+([0-9]+)[^0-9]+([0-9]+).*$/"
as there is nothing usually returned after the number of warnings. The previous expression required at least 1 non-digit character after the number of warnings.
sng2nara
02-Oct-2003 09:41
02-Oct-2003 09:41
You can use following code for choosing update or insert.
mysql_query($update_sql);
preg_match(
"/^[^0-9]+([0-9]+)[^0-9]+([0-9]+)[^0-9]+([0-9]+)[^0-9]+$/",
mysql_info(),
$arr);
if( $arr[1] == 0 ) // a number of matched rows is 0
{...do insert query...}
else
{...nothing...}
raistlin at oracolo dot com
03-Jul-2003 06:38
03-Jul-2003 06:38
| If you need to know the actual count of rows,
| even if some update changed nothing add a field
| count int(11) and add | one on every update, like in:
|
| mysql_query("update table set count=count+1, ...");
| if (mysql_affected_rows()==0) {
| mysql_query("insert into table ...");
| }
Better: add a field `flag` tinyint(1) unsigned default '0'
on every update: "update table set flag=1-flag, ..."
anthonyd at rhsonline dot net
03-Jul-2003 01:08
03-Jul-2003 01:08
My little work around for the update problem (that I ran into):
if (mysql_affected_rows()==0) {
$q = "select .. WHERE ...<search for what you updated>'";
if (mysql_num_rows(mysql_query($q))==0)
die("0 rows affected");
else
echo "Record Alredy Existed";
}
It is probably not the best way, as I sometimes run 2 queries for the same thing, but it gets the job done.
phpweb at eden2 dot com
28-Jun-2003 08:47
28-Jun-2003 08:47
"Note: When using UPDATE, MySQL will not update columns where the new value is the same as the old value. This creates the possiblity 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."
As of PHP 4.3.0 (I assume, I only tried with 4.3.2), you can make mysql_affected_rows() return the number of rows matched, even if none are updated.
You do this by setting the CLIENT_FOUND_ROWS flag in mysql_connect(). For some reason, not all the flags are defined in PHP, but you can use the decimal equivalent, which for CLIENT_FOUND_ROWS is 2.
So, for example:
$db= mysql_connect("localhost", "user", "pass", false, 2);
mysql_select_db("mydb", $db);
$query= "UPDATE ...";
mysql_query($query);
print mysql_affected_rows(); // more than 0
mysql_query($query); // same query twice
print mysql_affected_rows(); // still more than 0
gabriel dot preda at amr dot ro
18-Jun-2003 05:35
18-Jun-2003 05:35
-1-----------------------------
$w = "insert into...";
$q = mysql_query($w) or die('mortua est'); // 1433 times
print mysql_affected_rows($cnex); // prints 1433
-2-----------------------------
$w = "insert into...";
$q = mysql_query($w) or die('mortua est'); // 1433 times
@mysql_query("SELECT a FROM b LIMIT x"); //
print mysql_affected_rows($cnex); // prints x
It appears that php's "mysql_affected_rows" calls mysql's "mysql_affected_rows"... witch says:
"For SELECT statements, mysql_affected_rows() works like mysql_num_rows().
mysql_affected_rows() is currently implemented as a macro."
adam at NOSPAM dot example dot com
17-Jan-2003 08:34
17-Jan-2003 08:34
using PHP/MySql -There is an alternate way to get the rows returned -
for non-critical use i suppose--due to its oversimplified approach.
You can simply intialize a variable to the integer value of 0, and then, inside of the "while" loop that returns the rows
of your query, you increment that variable and then print out the final value of that variable outside of that "while" loop.
Or, you could print the variable within each iteration if you want to give each row returned [ as in a chart where you
need to provide line numbers ]
//code:
$sql = "SELECT * FROM YourTable
ORDER BY Last_Name";
$result = @mysql_query($sql, $connection) or die("Could not execute query.");
$i = 0; // we will use variable $i as a returned row counter.
while ($row = mysql_fetch_array($result)) {
$First_Name = $row['First_Name'];
$Last_Name = $row['Last_Name'];
$num_rows = mysql_num_rows($result);
$i++;
//To show the rows number by number
echo "Member no. $i $First_Name $Last_Name < br >";
// the < br > is an actual HTML line break
// which is not allowed on posting these notes,
// to use it, close up the spaces between the < and the >
// above echo statement will produce the results below if 3 rows were returned:
// Member no. 1 John Jones
// Member no. 2 Mary Smith
// Member no. 3 Nancy Steffan
}
echo "$i Rows Returned from query.";
// above statement will produce:
// 3 Rows Returned from query.
Hope this helps-- again,
this is a simplified approach.
take care;
<?adam?>
spam123 at cobsen dot biz
09-Dec-2002 02:04
09-Dec-2002 02:04
If you need to know the actual count of rows, even if some update changed nothing add a field count int(11) and add one on every update, like in:
mysql_query("update table set count=count+1, ...");
if (mysql_affected_rows()==0) {
mysql_query("insert into table ...");
}
ben-xo at NOSPAMdubplatesNOSPAM dot org
21-Apr-2002 04:30
21-Apr-2002 04:30
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
$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:
$query = "UPDATE ...";
mysql_query($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 09:06
13-Aug-2001 09:06
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.
peter at petermoulding dot NO_SPAM dot com
06-Aug-2001 08:34
06-Aug-2001 08:34
mysql_affected_rows() fails with some automatic updates. An example from the PHP Black Book is that of session records updated by automatic timestamps. When you maintain the session valid time via a timestamp and use some databases including MySQL, then update the session record, the automatic timestamp update will not count as an update in mysql_affected_rows(). You have to manually update the timestamp field. In MySQL that is achieved by setting the field to nulls. If your time field is named updated, you have to include
set updated = null
Other databases require appropriate tricks and you will have to test stored procedures in your database to see if their updates count in mysql_affected_rows().