Index: /trunk/FACT++/www/shift/calendar.php
===================================================================
--- /trunk/FACT++/www/shift/calendar.php	(revision 16812)
+++ /trunk/FACT++/www/shift/calendar.php	(revision 16813)
@@ -2,4 +2,16 @@
 
 require_once("config.php");
+
+function log_sql_error($query, $error)
+{
+    if (!file_exists("log/"))
+        mkdir("log/", 0777, true);
+
+    $file = fopen("log/mysql.log", "a");
+    fwrite($file, date("Y-m-d H:i:s")."\n".$query."\n".$error."\n\n");
+    fclose($file);
+
+    return header('HTTP/1.0 500 '.$error);
+}
 
 function login()
@@ -74,8 +86,8 @@
 
 if (!mysql_connect($dbhost, $dbuser, $dbpass))
-    return header('HTTP/1.0 500 '.mysql_error());
+    return log_sql_error("connect: ".$dbhost."[".$dbuser."]", mysql_error());
 
 if (!mysql_select_db($dbname))
-    return header('HTTP/1.0 500 '.mysql_error());
+    return log_sql_error("select_db: ".$dbname, mysql_error());
 
 if (isset($_GET['comment']))
@@ -87,5 +99,5 @@
     $result = mysql_query($query);
     if (!$result)
-        return header('HTTP/1.0 500 '.mysql_error());
+        return log_sql_error($query, mysql_error());
 
     if (isset($_GET['d']))
@@ -126,10 +138,15 @@
         $c = $_GET['c'];
 
-        if (!mysql_query("DELETE FROM Comments WHERE y=".$y." AND m=".$m." AND d=".$d))
-            return header('HTTP/1.0 500 '.mysql_error());
+        $query = "DELETE FROM Comments WHERE y=".$y." AND m=".$m." AND d=".$d;
+        if (!mysql_query($query))
+            return log_sql_error($query, mysql_error());
 
-        if (strlen($c)>0)
-            if (!mysql_query("INSERT Comments SET y=".$y.", m=".$m.", d=".$d.", c='".$c."'"))
-                return header('HTTP/1.0 500 '.mysql_error());
+        if (strlen($c)<=0)
+            return;
+
+        $query = "INSERT Comments SET y=".$y.", m=".$m.", d=".$d.", c='".$c."'";
+        if (!mysql_query($query))
+            return log_sql_error($query, mysql_error());
+
         return;
     }
@@ -137,12 +154,15 @@
     $u = isset($_GET['u']) ? $_GET['u'] : $_SERVER['PHP_AUTH_USER'];
 
-    if (!mysql_query("DELETE FROM Data WHERE y=".$y." AND m=".$m." AND d=".$d." AND u='".$u."'"))
-        return header('HTTP/1.0 500 '.mysql_error());
+    $query = "DELETE FROM Data WHERE y=".$y." AND m=".$m." AND d=".$d." AND u='".$u."'";
+    if (!mysql_query($query))
+        return log_sql_error($query, mysql_error());
 
     if (mysql_affected_rows()==0)
     {
-    	$x = $_GET['x'];
-        if (!mysql_query("INSERT Data SET y=".$y.", m=".$m.", d=".$d.", x=".$x.", u='".$u."'"))
-            return header('HTTP/1.0 500 '.mysql_error());
+        $x = $_GET['x'];
+
+        $query = "INSERT Data SET y=".$y.", m=".$m.", d=".$d.", x=".$x.", u='".$u."'";
+        if (!mysql_query($query))
+            return log_sql_error($query, mysql_error());
     }
 }
@@ -154,5 +174,6 @@
 $result = mysql_query($query);
 if (!$result)
-    return header('HTTP/1.0 500 '.mysql_error());
+    if (!mysql_query($query))
+        return log_sql_error($query, mysql_error());
 
 while ($row = mysql_fetch_array($result, MYSQL_NUM))