From b9ea2b7ad5c93888ffcf70a1446de9488c903fa9 Mon Sep 17 00:00:00 2001
From: tjhunt <tjhunt>
Date: Wed, 28 Feb 2007 17:19:04 +0000
Subject: [PATCH] Add a unique index to the question_numerical_units table, to
 prevent duplicate units being created.

---
 mod/quiz/db/install.xml |  5 ++++-
 mod/quiz/db/upgrade.php | 16 ++++++++++++++++
 mod/quiz/version.php    |  2 +-
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/mod/quiz/db/install.xml b/mod/quiz/db/install.xml
index 818e203806..f3e37aa0d8 100755
--- a/mod/quiz/db/install.xml
+++ b/mod/quiz/db/install.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<XMLDB PATH="mod/quiz/db" VERSION="20060920" COMMENT="XMLDB file for Moodle mod/quiz"
+<XMLDB PATH="mod/quiz/db" VERSION="20070228" COMMENT="XMLDB file for Moodle mod/quiz"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:noNamespaceSchemaLocation="../../../lib/xmldb/xmldb.xsd"
 >
@@ -114,6 +114,9 @@
         <KEY NAME="primary" TYPE="primary" FIELDS="id" COMMENT="Primary key for question_numerical_units" NEXT="question"/>
         <KEY NAME="question" TYPE="foreign" FIELDS="question" REFTABLE="question" REFFIELDS="id" PREVIOUS="primary"/>
       </KEYS>
+      <INDEXES>
+        <INDEX NAME="question-unit" UNIQUE="true" FIELDS="question, unit" COMMENT="Unique index to ensure that only one unit with a particular name is created for each question."/>
+      </INDEXES>
     </TABLE>
     <TABLE NAME="question_attempts" COMMENT="Student attempts. This table gets extended by the modules" PREVIOUS="question_numerical_units" NEXT="question_states">
       <FIELDS>
diff --git a/mod/quiz/db/upgrade.php b/mod/quiz/db/upgrade.php
index db8abd527b..d9b54353fb 100644
--- a/mod/quiz/db/upgrade.php
+++ b/mod/quiz/db/upgrade.php
@@ -32,6 +32,22 @@ function xmldb_quiz_upgrade($oldversion=0) {
 ///     $result = result of "/lib/ddllib.php" function calls
 /// }
 
+    if ($result && $oldversion < 2007022800) {
+    /// Ensure that there are not existing duplicate entries in the database.
+        delete_records_select('question_numerical_units', "id > (SELECT MIN(iqnu.id)
+                FROM {$CFG->prefix}question_numerical_units iqnu
+                WHERE iqnu.question = {$CFG->prefix}question_numerical_units.question AND
+                        iqnu.unit = {$CFG->prefix}question_numerical_units.unit)");
+
+    /// Define index question-unit (unique) to be added to question_numerical_units
+        $table = new XMLDBTable('question_numerical_units');
+        $index = new XMLDBIndex('question-unit');
+        $index->setAttributes(XMLDB_INDEX_UNIQUE, array('question', 'unit'));
+
+    /// Launch add index question-unit
+        $result = $result && add_index($table, $index);
+    }
+
     return $result;
 }
 
diff --git a/mod/quiz/version.php b/mod/quiz/version.php
index 05b940f7b1..30f67250df 100644
--- a/mod/quiz/version.php
+++ b/mod/quiz/version.php
@@ -5,7 +5,7 @@
 //  This fragment is called by moodle_needs_upgrading() and /admin/index.php
 ////////////////////////////////////////////////////////////////////////////////
 
-$module->version  = 2007020200;   // The (date) version of this module
+$module->version  = 2007022800;   // The (date) version of this module
 $module->requires = 2007020200;   // Requires this Moodle version
 $module->cron     = 0;            // How often should cron check this module (seconds)?
 
-- 
2.39.5