From 2d97513d12105058cffcf9dcba12e0095ec72edb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20S=CC=8Ckoda?= <commits@skodak.org>
Date: Wed, 17 Apr 2013 16:08:16 +0200
Subject: [PATCH] MDL-38972 add upgrade info for duplicate index-key problems

---
 lib/upgrade.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/upgrade.txt b/lib/upgrade.txt
index 19db0251d3a..a0236ef066f 100644
--- a/lib/upgrade.txt
+++ b/lib/upgrade.txt
@@ -65,6 +65,8 @@ information provided here is intended especially for developers.
 Database (DML) layer:
 * $DB->sql_empty() is deprecated, you have to use sql parameters with empty values instead,
   please note hardcoding of empty strings in SQL queries breaks execution in Oracle database.
+* Indexes must not be defined on the same columns as keys, this is now reported as fatal problem.
+  Please note that internally we create indexes instead of foreign keys.
 
 YUI changes:
 * M.util.help_icon has been deprecated. Code should be updated to use moodle-core-popuphelp