How to stop a code from working if the row is locked

[cliftonbazaar]

I have the following piece of code (if anyone can think of a better way then please tell me).

  mysql_query("BEGIN");
  #NOTE that we are only going to load in games that need to be updated so there is no need to set an IF statement
  if(@$my_team['inGame']) {$my_team_ID = $my_team['inGame'];} else{$my_team_ID=0;}
  $matches = mysql_query("SELECT * FROM matches
      WHERE completed=0 and $current_time > updateTime
      ORDER BY matchID ASC
      LOCK IN SHARE MODE ");  //Get all the matches that need updating
    while($match = mysql_fetch_array($matches)) {  //Go through all the matches that need updating
 	$notes .= "<p>MatchID - ".$match['matchID']." ".$match['homeTeam']." V ".$match['awayTeam'];
	$updateTime=$match['updateTime'];  #Get the updateTime from the match ID
	include("run_game.php");  #This is the actual file that runs the game
	$notes .= "<BR>This is the string data".$stringData."<BR>";  #Output it to make sure it works
    }
    mysql_query("COMMIT"); # Here the datarecords are released and the transaction is completed

This code works fine - the 'matches' database is only updated once; the problem is if it is run from two differant directions then ANOTHER part of the code in run_game.php is run and updated, this is not what I wanted

How can I get this query NOT to activate on locked rows?  I tried Google but I dont' know what to search for

[cliftonbazaar]

Bump

[ignace]

If you use FOR UPDATE with a storage engine that uses page or row locks, rows examined by the query are write-locked until the end of the current transaction. Using LOCK IN SHARE MODE sets a shared lock that permits other transactions to read the examined rows but not to update or delete them.

You need INNODB for this to work.

[cliftonbazaar]

You need INNODB for this to work.

 

Hi,

The actual locking of the row of the table is done correctly, but its till runs the code in the WHILE loop, I wish to make it that if the loop is locked the WHILE loop does NOT active.

Edited April 15, 2013 by cliftonbazaar