建立两张表：
CREATETABLE t_btree
ASSELECT *
FROM dba_objects
在t_btree上建立bitmap索引
createbitmapINDEX object_id_bmx
ont_btree(object_id);
执行两次查询
SELECT * FROM t_btree WHERE object_id=9999;
发现了执行了71次cr，扫描路径是bitmap索引
Drop index object_id_bmx
创建btree索引：
CREATE
INDEX object_id_btx
on t_btree(object_id);
执行两次查询
SELECT * FROM t_btree WHERE object_id=9999;
发现了执行了4次cr，扫描路径是index range，证明是btree索引