对于clob的数据,很多场合中都使用xml的格式,但是对于数据的查取和处理总是感觉力不从心。在条件允许的情况下,如果能够巧妙的使
对于clob的数据,很多场合中都使用xml的格式,但是对于数据的查取和处理总是感觉力不从心。在条件允许的情况下,如果能够巧妙的使用xmltype来做数据处理,无意中是对于clob的一个处理利器。
简单说下需求。
数据库里存放的clob类似下面的格式
现在有一个需求是能够把RelatedObjectInfo 中的objID查取,整理后得到一个以逗号分隔的串。
比如上面的clob数据,需要输出成为下面的形式:
##PC4.0##118146,##PC4.0##30369,##PC4.0##118145,##PC4.0##118211,##PC4.0##117696,##PC4.0##119094,##PC45.0##118203,
如果直接通过sql语句来写,确实很难实现,,如果通过Pl/sql也需要做不少的工作。
下面尝试使用xmltype来直接读取clob数据。
简单创建一个测试表,插入数据。
create table AA(id number,c_cml clob);
insert into aa values(5,to_clob('
'));
来看看xmltype的效果,根据根节点,找到最终的叶子节点。
select extract(xmltype(c_cml),'/ObjectInfo/Relations/RelationInfo/RelatedObjects/RelatedObjectInfo') a,
id
from aa where id=5;
A ID
---------------------------------------------------------------------------------------------------- --------
可以看到已经查到了
更进一步,把xml标记进行清除。可以直接使用replace
SQL> select replace(extract(xmltype(c_cml),'/ObjectInfo/Relations/RelationInfo/RelatedObjects/RelatedObjectInfo'),'
9094"/>##PC4.0##118203"/>##PC4.0##118133"/>##PC4.0##118135"/>##PC4.0##118583"/>##PC4.0##30313"/>##PC
4.0##30310"/>##PC4.0##110154"/>##PC4.0##30317"/>##PC4.0##30314"/>##PC4.0##30315"/>##PC4.0##30318"/>#
#PC4.0##118131"/>##PC4.0##30309"/>##PC4.0##118160"/>##PC4.0##119101"/>
然后直接清除尾部标记。
SQL> select replace(replace(extract(xmltype(c_cml),'/ObjectInfo/Relations/RelationInfo/RelatedObjects/RelatedObjectInfo'),'
2 id
3 from aa where id=5;
A ID
---------------------------------------------------------------------------------------------------- --------
##PC4.0##118146,##PC4.0##30369,##PC4.0##118145,##PC4.0##118211,##PC4.0##117696,##PC4.0##119094,##PC4 5
.0##118203,##PC4.0##118133,##PC4.0##118135,##PC4.0##118583,##PC4.0##30313,##PC4.0##30310,##PC4.0##11
0154,##PC4.0##30317,##PC4.0##30314,##PC4.0##30315,##PC4.0##30318,##PC4.0##118131,##PC4.0##30309,##PC
4.0##118160,##PC4.0##119101,
这样就能很快实现需求,把clob的数据当做xml来做处理,当然了对于clob的数据格式也是有一些限定的。
本文永久更新链接地址:

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