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Dropping one UNIQUE index over NULLable columns. It isn't

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cross-db at all. So we make the composite index not unique
to get speed benefits but the unique constraint is
controlled programatically.
This commit is contained in:
stronk7 2007-09-06 18:31:13 +00:00
parent 77d574a8c5
commit 4a039315d7
2 changed files with 34 additions and 4 deletions
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29
lib/db/upgrade.php
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@ -2034,6 +2034,35 @@ function xmldb_main_upgrade($oldversion=0) {
}
}
/// To have UNIQUE indexes over NULLable columns isn't cross-db at all
/// so we create a non unique index and programatically enforce uniqueness
if ($result && $oldversion < 2007090600) {
/// Define index idnumber (unique) to be dropped form course_modules
$table = new XMLDBTable('course_modules');
$index = new XMLDBIndex('idnumber');
$index->setAttributes(XMLDB_INDEX_UNIQUE, array('idnumber'));
/// Launch drop index idnumber
$result = $result && drop_index($table, $index);
/// Define index idnumber-course (not unique) to be added to course_modules
$table = new XMLDBTable('course_modules');
$index = new XMLDBIndex('idnumber-course');
$index->setAttributes(XMLDB_INDEX_NOTUNIQUE, array('idnumber', 'course'));
/// Launch add index idnumber-course
$result = $result && add_index($table, $index);
/// Define index idnumber-courseid (not unique) to be added to grade_items
$table = new XMLDBTable('grade_items');
$index = new XMLDBIndex('idnumber-courseid');
$index->setAttributes(XMLDB_INDEX_NOTUNIQUE, array('idnumber', 'courseid'));
/// Launch add index idnumber-courseid
$result = $result && add_index($table, $index);
}
/*