From 3aafe5bcb3ffa16061fe9165c272045e48cd02cd Mon Sep 17 00:00:00 2001
From: Dongsheng Cai <unoter@gmail.com>
Date: Tue, 4 May 2010 06:17:12 +0000
Subject: [PATCH] "MDL-22297, check if table field exists"

---
 mod/chat/db/upgrade.php | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mod/chat/db/upgrade.php b/mod/chat/db/upgrade.php
index 6c26cc3efec..b83e78c8774 100644
--- a/mod/chat/db/upgrade.php
+++ b/mod/chat/db/upgrade.php
@@ -48,7 +48,9 @@ function xmldb_chat_upgrade($oldversion) {
         $field = new xmldb_field('introformat', XMLDB_TYPE_INTEGER, '4', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, '0', 'intro');
 
     /// Launch add field introformat
-        $dbman->add_field($table, $field);
+        if (!$dbman->field_exists($table, $field)) {
+            $dbman->add_field($table, $field);
+        }
 
     /// chat savepoint reached
         upgrade_mod_savepoint($result, 2010050101, 'chat');