我正在运行Oracle BI Publisher 11g(11.1.1.3.0),并试图访问存储在数据库表中的XML数据。不幸的是我有几个问题,目前我很困惑。使用Oracle 11g BI Publisher创建XML数据的数据模型
我有一个表:
create table xml_test(
id number,
data1 clob,
data2 xmltype
);
desc xml_test
Name Null? Type
-------------------------------------------- -------- ---------------------------
ID NUMBER
DATA1 CLOB
DATA2 PUBLIC.XMLTYPE
充满了XML数据:
insert into xml_test values (
1,
to_clob(xmltype.createxml('<top><foo>I''m first foo !</foo><bar>I''m first bar !</bar></top>')),
xmltype.createxml('<top><foo>I''m first foo !</foo><bar>I''m first bar !</bar></top>')
);
insert into xml_test values (
2,
to_clob(xmltype.createxml('<top><foo>I''m second foo !</foo><bar>I''m second bar !</bar></top>')),
xmltype.createxml('<top><foo>I''m second foo !</foo><bar>I''m second bar !</bar></top>')
);
insert into xml_test values (
3,
to_clob(xmltype.createxml('<top><foo>I''m third foo !</foo><bar>I''m third bar !</bar></top>')),
xmltype.createxml('<top><foo>I''m third foo !</foo><bar>I''m third bar !</bar></top>')
);
commit;
我可以用sqlplus查询它:
column id format 99
column data1 format a35
column data2 like data1
select * from xml_test;
ID DATA1 DATA2
--- ----------------------------------- -----------------------------------
1 <top><foo>I'm first foo !</foo><bar <top>
>I'm first bar !</bar></top> <foo>I'm first foo !</foo>
<bar>I'm first bar !</bar>
</top>
2 <top><foo>I'm second foo !</foo><ba <top>
r>I'm second bar !</bar></top> <foo>I'm second foo !</foo>
<bar>I'm second bar !</bar>
</to
3 <top><foo>I'm third foo !</foo><bar <top>
>I'm third bar !</bar></top> <foo>I'm third foo !</foo>
<bar>I'm third bar !</bar>
</top>
select xt.id,
xmlcast(xmlquery('//foo' passing xt.data2 returning content) as varchar2(30)) "FOO",
xmlcast(xmlquery('//bar' passing xt.data2 returning content) as varchar2(30)) "BAR"
from xml_test xt;
ID FOO BAR
--- ------------------------------ ------------------------------
1 I'm first foo ! I'm first bar !
2 I'm second foo ! I'm second bar !
3 I'm third foo ! I'm third bar !
select xt.id, t.*
from xml_test xt,
xmltable('//top' passing xt.data2
columns "FOO" varchar2(15) path 'foo',
"BAR" varchar2(15) path 'bar') t;
ID FOO BAR
--- --------------- ---------------
1 I'm first foo ! I'm first bar !
2 I'm second foo I'm second bar
3 I'm third foo ! I'm third bar !
对我来说,一切都看起来不错,到目前为止,但是当我尝试在BI Publisher中创建数据模型时,遇到了几个问题。
根据Oracle文档Using Data Stored as a Character Large Object (CLOB) in a Data Model我应该能够在数据建模器中将data1列CLOB类型更改为XML类型。在我的安装中,我无法做到这一点,因为我永远不会提示文档中描述的下拉菜单。为什么这个选项不适合我?创建表的方式是错误的,或者是以错误的方式进行数据插入,还是以错误的方式安装或配置BI Publisher或Oracle数据库?或椅子和键盘之间的问题?然而,当我运行XML生成数据1的值显示(正确地)为CLOB:
<ID>1</ID>
<DATA1>
<top><foo>I'm first foo !</foo><bar>I'm first bar !</bar></top>
</DATA1>
<DATA2/>
但列数据2(即XMLTYPE类型)无法识别所有的XML但BI Publisher的表明它是一个字符串,并在生成XML时返回null(见上文)。
由于BI Publisher根本无法识别XMLTYPE,所以我尝试了一种解决方法。在BI Publisher的查询生成器执行以下操作:
select "XML_TEST"."ID" as "ID",
xmlcast(xmlquery('//foo' passing "XML_TEST"."DATA2" returning content) as varchar2(30)) as "FOO",
xmlcast(xmlquery('//bar' passing "XML_TEST"."DATA2" returning content) as varchar2(30)) as "BAR"
from "XML_TEST" "XML_TEST"
按预期工作:
<ID_1>1</ID_1>
<BAR>I'm first bar !</BAR>
<FOO>I'm first foo !</FOO>
但随后令人惊讶的(对我来说)这将失败:
/* This works on Query Builder but XML generation fails. */
select "xt"."ID" as "ID", t.bar_xml_test as "B1", t.foo_xml_test as "B2"
from "XML_TEST" "xt",
xmltable('//top' passing xt.data2
columns "foo_xml_test" varchar2(15) path 'foo',
"bar_xml_test" varchar2(15) path 'bar') as t
查询设计器认为这没关系,但XML生成失败:
XML Parsing Error: no element found
为什么xmlcast + xmlquery可以使用,但xmltable不能使用? BI Publisher不喜欢虚拟表吗?