Implemented random ordering for databases that support it

sys/db/query_builder.php

@@ -355,7 +355,11 @@ class Query_Builder {
 	 */
 	public function order_by($field, $type="")
 	{
-		// @todo Implement Order by Random
+		// Random case
+		if (stripos($type, 'rand') !== FALSE)
+		{
+			$type = (($rand = $this->sql->random()) !== FALSE ) ? $rand : 'ASC';
+		}
 	
 		// Set fields for later manipulation
 		$field = $this->db->quote_ident($field);
@@ -370,7 +374,9 @@ class Query_Builder {
 		}
 		
 		// Set the final string
-		$this->order_string = ' ORDER BY '.implode(',', $order_clauses);
+		$this->order_string = (empty($rand)) 
+			? ' ORDER BY '.implode(',', $order_clauses)
+			: ' ORDER BY'.$rand;
 		
 		return $this;
 	}

tests/databases/firebird-qb.php

@@ -120,6 +120,19 @@ class FirebirdQBTest extends UnitTestCase {
 		$this->assertTrue(is_resource($query));
 	}
 	
+	function TestOrderByRand()
+	{
+		$query = $this->qb->select('id, key as k, val')
+			->from('create_test')
+			->where('id >', 0)
+			->where('id <', 9000)
+			->order_by('id', 'rand')
+			->limit(5,2)
+			->get();
+			
+		$this->assertTrue(is_resource($query));
+	}
+	
 	/*function TestGroupBy()
 	{
 		$query = $this->qb->select('id, key as k, val')

tests/databases/sqlite-qb.php

@@ -114,6 +114,19 @@
 		$this->assertIsA($query, 'PDOStatement');
 	}
 	
+	function TestOrderByRandom()
+	{
+		$query = $this->qb->select('id, key as k, val')
+			->from('create_test')
+			->where('id >', 0)
+			->where('id <', 9000)
+			->order_by('id', 'rand')
+			->limit(5,2)
+			->get();
+			
+		$this->assertIsA($query, 'PDOStatement');
+	}
+	
 	function TestGroupBy()
 	{
 		$query = $this->qb->select('id, key as k, val')