/**
* Given one correct xmldb_index, returns the SQL statements
* needed to create it (in array).
*
* @param xmldb_table $xmldb_table The xmldb_table instance to create the index on.
* @param xmldb_index $xmldb_index The xmldb_index to create.
* @return array An array of SQL statements to create the index.
* @throws coding_exception Thrown if the xmldb_index does not validate with the xmldb_table.
*/
public function getCreateIndexSQL($xmldb_table, $xmldb_index)
{
$sqls = parent::getCreateIndexSQL($xmldb_table, $xmldb_index);
$hints = $xmldb_index->getHints();
$fields = $xmldb_index->getFields();
if (in_array('varchar_pattern_ops', $hints) and count($fields) == 1) {
// Add the pattern index and keep the normal one, keep unique only the standard index to improve perf.
foreach ($sqls as $sql) {
$field = reset($fields);
$count = 0;
$newindex = preg_replace("/^CREATE( UNIQUE)? INDEX ([a-z0-9_]+) ON ([a-z0-9_]+) \\({$field}\\)\$/", "CREATE INDEX \\2_pattern ON \\3 USING btree ({$field} varchar_pattern_ops)", $sql, -1, $count);
if ($count != 1) {
debugging('Unexpected getCreateIndexSQL() structure.');
continue;
}
$sqls[] = $newindex;
}
}
return $sqls;
}
