SQLServer XML數(shù)據(jù)的五種基本操作
2020-07-25 13:32:54
供稿：網(wǎng)友
1.xml.exist
輸入為XQuery表達(dá)式，返回0，1或是Null。0表示不存在，1表示存在，Null表示輸入為空
2.xml.value
輸入為XQuery表達(dá)式，返回一個(gè)SQL Server標(biāo)量值
3.xml.query
輸入為XQuery表達(dá)式，返回一個(gè)SQL Server XML類型流
4.xml.nodes
輸入為XQuery表達(dá)式，返回一個(gè)XML格式文檔的一列行集
5.xml.modify
使用XQuery表達(dá)式對(duì)XML的節(jié)點(diǎn)進(jìn)行insert , update 和 delete 操作。
下面通過(guò)例子對(duì)上面的五種操作進(jìn)行說(shuō)明：
declare @XMLVar xml = '
<catalog>
<book category="ITPro">
<title>Windows Step By Step</title>
<author>Bill Zack</author>
<price>49.99</price>
</book>
<book category="Developer">
<title>Developing ADO .NET</title>
<author>Andrew Brust</author>
<price>39.93</price>
</book>
<book category="ITPro">
<title>Windows Cluster Server</title>
<author>Stephen Forte</author>
<price>59.99</price>
</book>
</catalog>'
1. xml.exist
select @XMLVar.exist('/catalog/book')-----返回1
select @XMLVar.exist('/catalog/book/@category')-----返回1
select @XMLVar.exist('/catalog/book1')-----返回0
set @XMLVar = null
select @XMLVar.exist('/catalog/book')-----返回null
2.xml.value
select @XMLVar.value('/catalog[1]/book[1]','varchar(MAX)')
select @XMLVar.value('/catalog[1]/book[2]/@category','varchar(MAX)')
select @XMLVar.value('/catalog[2]/book[1]','varchar(MAX)')
結(jié)果集為：
Windows Step By StepBill Zack49.99 Developer NULL
3.xml.query
select @XMLVar.query('/catalog[1]/book')
select @XMLVar.query('/catalog[1]/book[1]')
select @XMLVar.query('/catalog[1]/book[2]/author')
結(jié)果集分別為：
<book category="ITPro">
<title>Windows Step By Step</title>
<author>Bill Zack</author>
<price>49.99</price>
</book>
<book category="Developer">
<title>Developing ADO .NET</title>
<author>Andrew Brust</author>
<price>39.93</price>
</book>
<book category="ITPro">
<title>Windows Cluster Server</title>
<author>Stephen Forte</author>
<price>59.99</price>
</book>
<book category="ITPro">
<title>Windows Step By Step</title>
<author>Bill Zack</author>
<price>49.99</price>
</book>
<author>Andrew Brust</author>
4.xml.nodes
select T.c.query('.') as result from @XMLVar.nodes('/catalog/book') as T(c)
select T.c.query('title') as result from @XMLVar.nodes('/catalog/book') as T(c)
結(jié)果集分別為：
<book category="ITPro"><title>Windows Step By Step</title><author>Bill …………
<book category="Developer"><title>Developing ADO .NET</title><author>Andrew …………
<book category="ITPro"><title>Windows Cluster Server</title><author>Stephen …………
<title>Windows Step By Step</title>
<title>Developing ADO .NET</title>
<title>Windows Cluster Server</title>
5.xml.modify
關(guān)于modify內(nèi)容，請(qǐng)參見下一篇文章。
