From a326872b88d02ddf7cb0b6eb51f6a92aa5c323fd Mon Sep 17 00:00:00 2001
From: stronk7 <stronk7>
Date: Thu, 15 May 2008 17:02:05 +0000
Subject: [PATCH] prevent NULL contents before field change (old servers can
 have this wrongly defined). MDL-14859

---
 lib/db/upgrade.php | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index 8a7f91575bd..fbe1268941a 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -2970,6 +2970,11 @@ function xmldb_main_upgrade($oldversion=0) {
     if ($result && $oldversion < 2007101512) {
         notify('Increasing size of user idnumber field, this may take a while...', 'notifysuccess');
 
+    /// Under MySQL and Postgres... detect old NULL contents and change them by correct empty string. MDL-14859
+        if ($CFG->dbfamily == 'mysql' || $CFG->dbfamily == 'postgres') {
+            execute_sql("UPDATE {$CFG->prefix}user SET idnumber = '' WHERE idnumber IS NULL", true);
+        }
+
     /// Define index idnumber (not unique) to be dropped form user
         $table = new XMLDBTable('user');
         $index = new XMLDBIndex('idnumber');