Question

我需要从各种元素的长列表中提取所有属性。因此，我试图构建一个循环遍历所有元素并返回其属性。

通过几个帖子，我已经能够编写下面的代码了。但是，我有超过1000个元素，为什么我会非常高兴，如果以某种方式可以围绕后一部分构建循环而不是为所有元素复制它。

with cte as
(
select cast(
'<schema fwRel="2"> 
<taxFormId isPrimeKey="true" fkRef="C1-TXFRM" mapField="TAX_FORM_ID" dataType="string"/>  
<formType fkRef="C1-FRMTY" mapField="FORM_TYPE_CD" dataType="string"/>  
<bo suppress="true" required="true" fkRef="F1-BUSOB" mapField="BUS_OBJ_CD" dataType="string"/>
<transferReason mdField="C1_TXF_TFRRSN_FLG" dataType="lookup" mapXML="BO_DATA_AREA" lookup="C1_TXF_TFRRSN_FLG"/>  
</schema>' as xml) xml_col
)

select cte.xml_col.value('(/schema/taxFormId/@fkRef)[1]', 'varchar(100)') as Dummy1
cte.xml_col.value('(/schema/taxFormId/@mapField)[1]', 'varchar(100)') as Dummy2
cte.xml_col.value('(/schema/taxFormId/@dataType)[1]', 'varchar(100)') as Dummy3
cte.xml_col.value('(/schema/taxFormId/@mapXML)[1]', 'varchar(100)') as Dummy4

from cte

我希望我提供了足够的信息

Answer 1

列出属性的简便方法：

with cte as
(
select cast(
'<schema fwRel="2">
  <taxFormId isPrimeKey="true" fkRef="C1-TXFRM" mapField="TAX_FORM_ID" dataType="string" />
  <formType fkRef="C1-FRMTY" mapField="FORM_TYPE_CD" dataType="string" />
  <bo suppress="true" required="true" fkRef="F1-BUSOB" mapField="BUS_OBJ_CD" dataType="string" />
  <transferReason mdField="C1_TXF_TFRRSN_FLG" dataType="lookup" mapXML="BO_DATA_AREA" lookup="C1_TXF_TFRRSN_FLG" />
</schema>' as xml) xml_col
)

- 查询使用.nodes(N'/schema/*')列出<schema>和.nodes(N'@*')下的所有节点，以列出此节点中的所有属性：

select nd.value(N'local-name(.)',N'nvarchar(max)') AS NodeName
      ,attr.value(N'local-name(.)',N'nvarchar(max)') AS AttrName
      ,attr.value(N'.',N'nvarchar(max)') AS AttrValue
from cte
OUTER APPLY xml_col.nodes(N'/schema/*') AS A(nd)
OUTER APPLY A.nd.nodes(N'@*') AS B(attr)

结果：

taxFormId       isPrimeKey  true
taxFormId       fkRef       C1-TXFRM
taxFormId       mapField    TAX_FORM_ID
taxFormId       dataType    string
formType        fkRef       C1-FRMTY
formType        mapField    FORM_TYPE_CD
formType        dataType    string
bo              suppress    true
bo              required    true
bo              fkRef       F1-BUSOB
bo              mapField    BUS_OBJ_CD
bo              dataType    string
transferReason  mdField     C1_TXF_TFRRSN_FLG
transferReason  dataType    lookup
transferReason  mapXML      BO_DATA_AREA
transferReason  lookup      C1_TXF_TFRRSN_FLG

如果您需要类似于示例中的语句，可以动态创建它（作为字符串）并使用EXEC执行此操作（动态SQL ）。

Answer 2

它可能有点过度杀戮，但我经常使用TVF来解析和散列大型XML文件。该函数将使用范围键R1 / R2返回父/子层次结构中的数据。

例如：

Declare @XML xml='
<schema fwRel="2"> 
    <taxFormId isPrimeKey="true" fkRef="C1-TXFRM" mapField="TAX_FORM_ID" dataType="string"/>  
    <formType fkRef="C1-FRMTY" mapField="FORM_TYPE_CD" dataType="string"/>  
    <bo suppress="true" required="true" fkRef="F1-BUSOB" mapField="BUS_OBJ_CD" dataType="string"/>
    <transferReason mdField="C1_TXF_TFRRSN_FLG" dataType="lookup" mapXML="BO_DATA_AREA" lookup="C1_TXF_TFRRSN_FLG"/>
</schema>'

Select * from [dbo].[udf-XML-Hier](@XML) Order by R1

返回

您会注意到元素名称，属性名称，XPath，标题（可选）和值都有列。 R1，R2，Lvl，ID和PT都是派生的。

作为TVF，您可以应用任何WHERE或ORDER所需的

UDF（原始来源）如有兴趣

CREATE FUNCTION [dbo].[udf-XML-Hier](@XML xml)

Returns Table 
As Return

with  cte0 as ( 
                  Select Lvl       = 1
                        ,ID        = Cast(1 as int) 
                        ,Pt        = Cast(NULL as int)
                        ,Element   = x.value('local-name(.)','varchar(150)')
                        ,Attribute = cast('' as varchar(150))
                        ,Value     = x.value('text()[1]','varchar(max)')
                        ,XPath     = cast(concat(x.value('local-name(.)','varchar(max)'),'[' ,cast(Row_Number() Over(Order By (Select 1)) as int),']') as varchar(max))
                        ,Seq       = cast(10000001 as varchar(max))
                        ,AttData   = x.query('.') 
                        ,XMLData   = x.query('*') 
                  From   @XML.nodes('/*') a(x) 
                  Union  All
                  Select Lvl       = p.Lvl + 1 
                        ,ID        = Cast( (Lvl + 1) * 1024 + (Row_Number() Over(Order By (Select 1)) * 2) as int ) * 10
                        ,Pt        = p.ID
                        ,Element   = c.value('local-name(.)','varchar(150)')
                        ,Attribute = cast('' as varchar(150))
                        ,Value     = cast( c.value('text()[1]','varchar(max)') as varchar(max) ) 
                        ,XPath     = cast(concat(p.XPath,'/',c.value('local-name(.)','varchar(max)'),'[',cast(Row_Number() Over(PARTITION BY c.value('local-name(.)','varchar(max)') Order By (Select 1)) as int),']') as varchar(max) )
                        ,Seq       = cast(concat(p.Seq,' ',10000000+Cast( (Lvl + 1) * 1024 + (Row_Number() Over(Order By (Select 1)) * 2) as int ) * 10) as varchar(max))
                        ,AttData   = c.query('.') 
                        ,XMLData   = c.query('*') 
                  From   cte0 p 
                  Cross  Apply p.XMLData.nodes('*') b(c) 
              )
    , cte1 as (   
                  Select R1 = Row_Number() over (Order By Seq),A.*
                  From  (
                          Select  Lvl,ID,Pt,Element,Attribute,Value,XPath,Seq From cte0
                          Union All
                          Select Lvl       = p.Lvl+1
                                ,ID        = p.ID + Row_Number() over (Order By (Select NULL)) 
                                ,Pt        = p.ID
                                ,Element   = p.Element
                                ,Attribute = x.value('local-name(.)','varchar(150)')
                                ,Value     = x.value('.','varchar(max)')
                                ,XPath     = p.XPath + '/@' + x.value('local-name(.)','varchar(max)')
                                ,Seq       = cast(concat(p.Seq,' ',10000000+p.ID + Row_Number() over (Order By (Select NULL)) ) as varchar(max))
                          From   cte0 p 
                          Cross  Apply AttData.nodes('/*/@*') a(x) 
                        ) A 
               )

Select A.R1
      ,R2  = IsNull((Select max(R1) From cte1 Where Seq Like A.Seq+'%'),A.R1)
      ,A.Lvl
      ,A.ID
      ,A.Pt
      ,A.Element
      ,A.Attribute
      ,A.XPath
      ,Title = Replicate('|---',Lvl-1)+Element+IIF(Attribute='','','@'+Attribute)
      ,A.Value
 From  cte1 A

/*
Source: http://beyondrelational.com/modules/2/blogs/28/posts/10495/xquery-lab-58-select-from-xml.aspx

Declare @XML xml='<person><firstname preferred="Annie" nickname="BeBe">Annabelle</firstname><lastname>Smith</lastname></person>'
Select * from [dbo].[udf-XML-Hier](@XML) Order by R1
*/

用于提取元素XML属性的循环

2 个答案: