xml in oracle遇到單行子查詢返回多行

這裏是我創建表和插入xml列的代碼。xml in oracle遇到單行子查詢返回多行

--drop模式

BEGIN 
DBMS_XMLSCHEMA.DELETESCHEMA(
    'http://xmlns.oracle.com/xdb/schemas/HZHE18/handBook', 
    dbms_xmlschema.DELETE_CASCADE_FORCE); 
END;

--register的二進制模式

BEGIN 
DBMS_XMLSCHEMA.REGISTERSCHEMA(SCHEMAURL => 'handBook', 
schemadoc => '<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified"> 

<xs:annotation> 
    <xs:documentation> Author: Andy(Haichuan) Zheng Schema for Web Handbook data 
    </xs:documentation> 
</xs:annotation> 

<xs:simpleType name="code-style"> 
    <xs:restriction base="xs:string"> 
     <xs:pattern value="[A-Z][A-Z][A-Z][0-9][0-9][0-9][0-9]"/> 
    </xs:restriction> 
</xs:simpleType> 

<xs:simpleType name="level-style"> 
    <xs:restriction base="xs:string"> 
     <xs:enumeration value="Undergraduate"/> 
     <xs:enumeration value="Postgraduate"/> 
    </xs:restriction> 
</xs:simpleType> 

<xs:simpleType name="email-style"> 
    <xs:restriction base="xs:string"> 
     <xs:pattern value="[^@][email protected][^\.]+\..+"/> 
    </xs:restriction> 
</xs:simpleType> 

<xs:simpleType name="point_lvl_type"> 
    <xs:restriction base="xs:positiveInteger"> 
     <xs:enumeration value="3"/> 
     <xs:enumeration value="6"/> 
     <xs:enumeration value="12"/> 
     <xs:enumeration value="24"/> 
    </xs:restriction> 
</xs:simpleType> 

<xs:simpleType name="offered_type"> 
    <xs:restriction base="xs:string"> 
     <xs:enumeration value="First semester"/> 
     <xs:enumeration value="Second semester"/> 
    </xs:restriction> 
</xs:simpleType> 

<xs:simpleType name="mode_type"> 
    <xs:restriction base="xs:string"> 
     <xs:enumeration value="Day"/> 
     <xs:enumeration value="Evening"/> 
     <xs:enumeration value="Off-campus"/> 
    </xs:restriction> 
</xs:simpleType> 

<xs:simpleType name="campus_type"> 
    <xs:restriction base="xs:string"> 
     <xs:enumeration value="Caulfield"/> 
     <xs:enumeration value="Gippsland"/> 
     <xs:enumeration value="Sunway"/> 
     <xs:enumeration value="Clayton"/> 
     <xs:enumeration value="South Africa"/> 
    </xs:restriction> 
</xs:simpleType> 

<xs:element name="handbook"> 
    <xs:complexType> 
     <xs:sequence> 
      <xs:element ref="page_info" minOccurs="1" maxOccurs="unbounded"/> 
      <xs:element ref="unit" minOccurs="1" maxOccurs="unbounded"/> 
     </xs:sequence> 
    </xs:complexType> 
</xs:element> 

<xs:element name="page_info"> 
    <xs:complexType> 
     <xs:sequence> 
      <xs:element name="sub_date" type="xs:date"/> 
     </xs:sequence> 
     <xs:attribute name="author" type="xs:string"/> 
    </xs:complexType> 
</xs:element> 

<xs:element name="unit"> 
    <xs:complexType> 
     <xs:sequence> 
      <xs:element name="u_name" type="xs:string"/> 
      <xs:element name="level" type="level-style"/> 
      <xs:element ref="chief_examiner"/> 
      <xs:element name="point_lvl" type="point_lvl_type"/> 
      <xs:element name="prerequisites" type="code-style" maxOccurs="unbounded" 
       minOccurs="0"/> 
      <xs:element name="prohibitions" type="code-style" maxOccurs="unbounded" 
       minOccurs="0"/> 
      <xs:element ref="availability"/> 
      <xs:element name="synopsis" type="xs:string"/> 
      <xs:element name="assessment" type="xs:string"/> 
      <xs:element name="contact_hours" type="xs:string"/> 
     </xs:sequence> 
     <xs:attribute name="code" type="code-style"/> 
    </xs:complexType> 
</xs:element> 

<xs:element name="chief_examiner"> 
    <xs:complexType> 
     <xs:sequence> 
      <xs:element name="name" type="xs:string"/> 
      <xs:element name="email" type="email-style"/> 
     </xs:sequence> 
    </xs:complexType> 
</xs:element> 

<xs:element name="availability"> 
    <xs:complexType> 
     <xs:sequence> 
      <xs:element name="offered" type="offered_type" maxOccurs="unbounded"/> 
      <xs:element name="mode" type="mode_type" maxOccurs="unbounded"/> 
      <xs:element name="campus" type="campus_type" maxOccurs="unbounded"/> 
     </xs:sequence> 
    </xs:complexType> 
</xs:element> 

</xs:schema>', 
LOCAL => TRUE, 
GENTYPES => FALSE, 
GENTABLES => FALSE, 
FORCE => FALSE, 
options => DBMS_XMLSCHEMA.REGISTER_BINARYXML); 
end;

--drops和清潔回收站

drop table units_handbook purge; 

PURGE RECYCLEBIN;

--create表 CREATE TABLE units_handbook（ unit_code varchar2（7）PRIMARY KEY， XML_detail XMLTYPE NOT NULL） XMLTYPE COLUMN XML_detail STORE AS BINARY XML XMLSCHEMA 「http://xmlns.oracle.com/xdb/schemas/HZHE18/handBook」 ELEMENT「handbook」;

- 填充表

insert into units_handbook values('FIT2077', 
'<handbook> 
    <page_info author = "Haichuan Zheng"> 
     <sub_date>2013-05-28</sub_date> 
    </page_info> 
    <unit code="FIT2077"> 
     <u_name>Advanced Data Management</u_name> 
     <level>Undergraduate</level> 
     <chief_examiner> 
      <name>Mr Lindsay Smith</name> 
      <email>[email protected]</email> 
     </chief_examiner> 
     <point_lvl>6</point_lvl> 
     <prerequisites>FIT1004</prerequisites> 
     <prerequisites>CSE2132</prerequisites> 
    <prohibitions>CSE3000</prohibitions> 
     <prohibitions>FIT3118</prohibitions> 
    <prohibitions>FIT4038</prohibitions> 
    <availability> 
     <offered>First semester</offered> 
     <mode>Day</mode> 
     <campus>Caulfield</campus> 
    </availability> 
    <synopsis><![CDATA[This unit extends the study from FIT1004 Data management. 
     FIT2077 will introduce more advanced concepts in the areas of database design, SQL, 
     query optimisation and the handling of unstructured data (XML) both externally 
     and within a database. The issue of "Big Data" and the role played by BI technologies 
     and data warehouses will be explored.]]></synopsis> 
    <assessment>Examination (3 hours): 60%; In-semester assessment: 40%</assessment> 
    <contact_hours>2 hrs lectures/wk, 2 hrs laboratories/wk</contact_hours> 
</unit> 
</handbook>'); 

insert into units_handbook values('FIT4038', 
'<handbook> 
<page_info author = "Haichuan Zheng"> 
    <sub_date>2013-05-28</sub_date> 
</page_info> 
<unit code="FIT4038"> 
    <u_name>Database management and implementation</u_name> 
    <level>Postgraduate</level> 
    <chief_examiner> 
     <name>Associate Professor David Taniar</name> 
     <email>[email protected]</email> 
    </chief_examiner> 
    <point_lvl>6</point_lvl> 
    <prerequisites>FIT9019</prerequisites> 
    <prerequisites>FIT9003</prerequisites> 
    <prohibitions>FIT3118</prohibitions> 
    <prohibitions>CSE3000</prohibitions> 
    <availability> 
     <offered>First semester</offered> 
     <mode>Day</mode> 
     <campus>Caulfield</campus> 
    </availability> 
    <synopsis><![CDATA[This unit looks at the design and implementation issues of 
     database management systems. Advanced database design using the object-relational approach 
     and multi-dimensional database design are explored. Record, file 
     and index structures are dealt with at the basic level. 
     Higher level details of consistency, atomicity and durability are 
     introduced along with modern trends in databases.]]></synopsis> 
    <assessment>Examination (3 hours): 60%; In-semester assessment: 40%</assessment> 
    <contact_hours>2 hrs lectures/wk, 2 hrs laboratories/wk</contact_hours> 
</unit> 
</handbook>');

我的問題是，當我想檢索XML格式內的所有u_name我得到這個錯誤說ORA-01427：單行子查詢返回不止一行

這是我的代碼

select xmlelement("unit",xmlelement("u_name", 
    (
    SELECT 
     EXTRACTVALUE(u.XML_detail, '/handbook/unit/u_name') 
    FROM 
     units_handbook u 
) 
)) 
    from units_handbook;

來源

2013-05-30 A Web-Developer

這是因爲您的內部查詢返回多個行（因爲它在整個表上運行）。

爲什麼你就不能這樣做：

select xmlelement("unit",xmlelement("u_name",EXTRACTVALUE(u.XML_detail, '/handbook/unit/u_name') 
    )) 
    from units_handbook u;

如果你必須有它的內部查詢（SELECT子句中），那麼你會莫名其妙地需要連接記錄或確保您有隻有一行。
作爲

select xmlelement("unit",xmlelement("u_name", 
    (
    SELECT 
     EXTRACTVALUE(u.XML_detail, '/handbook/unit/u_name') 
    FROM 
     units_handbook u 
    WHERE u.id = ou.id 
) 
)) 
    from units_handbook ou;

Here is a sqlfiddle demo

來源

2013-05-30 08:31:00

涼爽，我被笨，洛爾。 –

xml in oracle遇到單行子查詢返回多行

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