Fix _limit()
diff --git a/system/database/drivers/cubrid/cubrid_driver.php b/system/database/drivers/cubrid/cubrid_driver.php
index 1cfaf3e..b89746b 100644
--- a/system/database/drivers/cubrid/cubrid_driver.php
+++ b/system/database/drivers/cubrid/cubrid_driver.php
@@ -696,7 +696,7 @@
 	 */
 	protected function _limit($sql, $limit, $offset)
 	{
-		return $sql.'LIMIT '.($offset == 0 ? '' : ', ').$limit;
+		return $sql.'LIMIT '.($offset == 0 ? '' : $offset.', ').$limit;
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/cubrid/cubrid_forge.php b/system/database/drivers/cubrid/cubrid_forge.php
index d277ca3..4b1c283 100644
--- a/system/database/drivers/cubrid/cubrid_forge.php
+++ b/system/database/drivers/cubrid/cubrid_forge.php
@@ -89,13 +89,13 @@
 				$attributes = array_change_key_case($attributes, CASE_UPPER);
 
 				$sql .= "\n\t\"".$this->db->protect_identifiers($field).'"'
-					.(isset($attributes['NAME']) ? ' '.$this->db->protect_identifiers($attributes['NAME']).' ' : '');
+					.( ! empty($attributes['NAME']) ? ' '.$this->db->protect_identifiers($attributes['NAME']).' ' : '');
 
 				if ( ! empty($attributes['TYPE']))
 				{
 					$sql .= ' '.$attributes['TYPE'];
 
-					if (isset($attributes['CONSTRAINT']))
+					if ( ! empty($attributes['CONSTRAINT']))
 					{
 						switch ($attributes['TYPE'])
 						{
@@ -125,9 +125,9 @@
 			 */
 
 				$sql .= (isset($attributes['DEFAULT']) ? " DEFAULT '".$attributes['DEFAULT']."'" : '')
-					.((isset($attributes['NULL']) && $attributes['NULL'] === TRUE) ? ' NULL' : ' NOT NULL')
-					.((isset($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE) ? ' AUTO_INCREMENT' : '')
-					.((isset($attributes['UNIQUE']) && $attributes['UNIQUE'] === TRUE) ? ' UNIQUE' : '');
+					.(( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE) ? ' NULL' : ' NOT NULL')
+					.(( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE) ? ' AUTO_INCREMENT' : '')
+					.(( ! empty($attributes['UNIQUE']) && $attributes['UNIQUE'] === TRUE) ? ' UNIQUE' : '');
 			}
 
 			// don't add a comma on the end of the last field