These commands are used with explicit cursors. First, the cursor is opened to make it active using the OPEN command. Then, the FETCH command is used to retrieve the rows from the active cursor. After all the rows are retrieved, the cursor is closed using the CLOSE command that can again be reopened. Any other operation on a closed cursor returns the predefined exception, INVALID_CURSOR. However, these commands cannot be used to control the SQL implicit cursors.