Added one new function find_key_name() to retrieve the

name og any key in the DB. This hasn't too much sense
for now (until we start to use referencial integrity) and
it is far from perfect, because it doesn't seach for the
key really in DB (due to the lack of support for this of ADOdb).

lib/ddllib.php

@@ -239,6 +239,61 @@ function table_column($table, $oldfield, $field, $type='integer', $size='10',
     }
 }
 
+/**
+ * This function IS NOT IMPLEMENTED. ONCE WE'LL BE USING RELATIONAL
+ * INTEGRITY IT WILL BECOME MORE USEFUL. FOR NOW, JUST CALCULATE "OFFICIAL"
+ * KEY NAMES WITHOUT ACCESSING TO DB AT ALL.
+ * Given one XMLDBKey, the function returns the name of the key in DB (if exists)
+ * of false if it doesn't exist
+ *
+ * @uses, $db
+ * @param XMLDBTable the table to be searched
+ * @param XMLDBKey the key to be searched
+ * @return string key name of false
+ */
+function find_key_name($xmldb_table, $xmldb_key) {
+
+    global $CFG, $db;
+
+/// Extract key columns
+    $keycolumns = $xmldb_key->getFields();
+
+/// Get list of keys in table
+/// first primaries (we aren't going to use this now, because the MetaPrimaryKeys is awful)
+    ///TODO: To implement when we advance in relational integrity
+/// then uniques (note that Moodle, for now, shouldn't have any UNIQUE KEY for now, but unique indexes)
+    ///TODO: To implement when we advance in relational integrity (note that AdoDB hasn't any MetaXXX for this.
+/// then foreign (note that Moodle, for now, shouldn't have any FOREIGN KEY for now, but indexes)
+    ///TODO: To implement when we advance in relational integrity (note that AdoDB has one MetaForeignKeys()
+    ///but it's far from perfect.
+/// TODO: To create the proper functions inside each generator to retrieve all the needed KEY info (name
+///       columns, reftable and refcolumns
+
+/// So all we do is to return the official name of the requested key without any confirmation!)
+    $classname = 'XMLDB' . $CFG->dbtype;
+    $generator = new $classname();
+    $generator->setPrefix($CFG->prefix);
+/// One exception, harcoded primary constraint names
+    if ($generator->primary_key_name && $xmldb_key->getType() == XMLDB_KEY_PRIMARY) {
+        return $generator->primary_key_name;
+    } else {
+    /// Calculate the name suffix
+        switch ($xmldb_key->getType()) {
+            case XMLDB_KEY_PRIMARY:
+                $suffix = 'pk';
+                break;
+            case XMLDB_KEY_UNIQUE:
+                $suffix = 'uk';
+                break;
+            case XMLDB_KEY_FOREIGN:
+                $suffix = 'fk';
+                break;
+        }
+    /// And simply, return the oficial name
+        return $generator->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), $suffix);
+    }
+}
+
 /**
  * Given one XMLDBIndex, the function returns the name of the index in DB (if exists)
  * of false if it doesn't exist