在 SQL 中添加 XML 模式引用

Question

如果可以在我的 XML 根目录中添加对架构的直接引用，我终生都找不到。

这是我的代码：

Declare @Employee table (EmployeeID int,First_Name varchar(50),Last_Name varchar(50))
    Insert into @Employee values
    (1,'John','Smith'),
    (2,'Jane','Doe'  )


    Select (Select CreatedBy='My Organization',CreateDate=GetDate() For XML Path('RecordHeader'),Type ) 
          ,(Select * From @Employee For XML Path('Employee'),Type ) 
    For XML Path ('Employees'),Type

这会产生以下结果：

<Employees>
  <RecordHeader>
    <CreatedBy>My Organization</CreatedBy>
    <CreateDate>2016-10-18T16:09:48.110</CreateDate>
  </RecordHeader>
  <Employee>
    <EmployeeID>1</EmployeeID>
    <First_Name>John</First_Name>
    <Last_Name>Smith</Last_Name>
  </Employee>
  <Employee>
    <EmployeeID>2</EmployeeID>
    <First_Name>Jane</First_Name>
    <Last_Name>Doe</Last_Name>
  </Employee>
</Employees>

有没有办法在我的 SQL 中添加部分以使根标记包含以下内容：

<Employees xmlns="https://www.blahblah.org/blahblah/BlahSchema.xsd">

感谢您的帮助！

Answer 1

xmlns 总是有问题，所以我用了一点 hack

Declare @Employee table (EmployeeID int,First_Name varchar(50),Last_Name varchar(50))
Insert into @Employee values
(1,'John','Smith'),
(2,'Jane','Doe'  )

Declare @XML xml = (
Select (Select CreatedBy='My Organization',CreateDate=GetDate() For XML Path('RecordHeader'),Type ) 
      ,(Select * From @Employee For XML Path('Employee'),Type ) 
For XML Path ('Employees'),Type
)

set @XML.modify('insert ( attribute MyNameSpace {"https://www.blahblah.org/blahblah/BlahSchema.xsd"}) into (/Employees)[1]')
set @XML = replace(cast(@XML as nvarchar(max)),'[MyNameSpace]','xmlns')

Select @XML

返回

<Employees xmlns="https://www.blahblah.org/blahblah/BlahSchema.xsd">
  <RecordHeader>
    <CreatedBy>My Organization</CreatedBy>
    <CreateDate>2017-01-10T15:19:42.873</CreateDate>
  </RecordHeader>
  <Employee>
    <EmployeeID>1</EmployeeID>
    <First_Name>John</First_Name>
    <Last_Name>Smith</Last_Name>
  </Employee>
  <Employee>
    <EmployeeID>2</EmployeeID>
    <First_Name>Jane</First_Name>
    <Last_Name>Doe</Last_Name>
  </Employee>
</Employees>

编辑以排除空值

NULL 默认会被忽略，所以如果你想排除空值（非空），你可以通过 NullIf() 将值转换为 NULL。例如

Declare @Employee table (EmployeeID int,First_Name varchar(50),Last_Name varchar(50))
Insert into @Employee values
(1,'John','Smith'),
(2,'Jane','Doe'  ),
(3,'Betty',null  ),  -- No element for Last_Name
(4,'Susan',''  )     -- No element for Last_Name

Declare @XML xml = (
Select (Select CreatedBy='My Organization',CreateDate=GetDate() For XML Path('RecordHeader'),Type ) 
      ,(Select EmployeeID = NullIf(EmployeeID,'') 
              ,First_Name = NullIf(First_Name,'')
              ,Last_Name  = NullIf(Last_Name,'')
         From  @Employee For XML Path('Employee'),Type ) 
For XML Path ('Employees'),Type
)

set @XML.modify('insert ( attribute MyNameSpace {"https://www.blahblah.org/blahblah/BlahSchema.xsd"}) into (/Employees)[1]')
set @XML = replace(cast(@XML as nvarchar(max)),'[MyNameSpace]','xmlns')

Select @XML

Answer 2

您可以使用WITH NAMESPACES 关键字，但这会将名称空间添加到所有节点：

Declare @Employee table (EmployeeID int,First_Name varchar(50),Last_Name varchar(50))
Insert into @Employee values
(1,'John','Smith'),
(2,'Jane','Doe'  );


WITH XMLNAMESPACES (DEFAULT 'https://www.blahblah.org/blahblah/BlahSchema.xsd')
Select (Select CreatedBy='My Organization',CreateDate=GetDate() For XML Path('RecordHeader'),Type ) 
      ,(Select * From @Employee For XML Path('Employee'),Type ) 
For XML Path ('Employees'),Type

结果：

<Employees xmlns="https://www.blahblah.org/blahblah/BlahSchema.xsd">
  <RecordHeader xmlns="https://www.blahblah.org/blahblah/BlahSchema.xsd">
    <CreatedBy>My Organization</CreatedBy>
    <CreateDate>2017-01-10T16:36:23.450</CreateDate>
  </RecordHeader>
  <Employee xmlns="https://www.blahblah.org/blahblah/BlahSchema.xsd">
    <EmployeeID>1</EmployeeID>
    <First_Name>John</First_Name>
    <Last_Name>Smith</Last_Name>
  </Employee>
  <Employee xmlns="https://www.blahblah.org/blahblah/BlahSchema.xsd">
    <EmployeeID>2</EmployeeID>
    <First_Name>Jane</First_Name>
    <Last_Name>Doe</Last_Name>
  </Employee>
</Employees>