* @return an array containing the column name list and the data list
*/
protected static Object[][] parseKey(Connection conn, String key) {
ArrayList<String> columns = New.arrayList();
ArrayList<String> data = New.arrayList();
JdbcConnection c = (JdbcConnection) conn;
Session session = (Session) c.getSession();
Parser p = new Parser(session);
Expression expr = p.parseExpression(key);
addColumnData(columns, data, expr);
Object[] col = new Object[columns.size()];
columns.toArray(col);