我有三个表table1, table2, table3，col1, col2和标识ID列。这些表关系在数据库中定义。
我正在尝试创建一个接受xml字符串输入的存储过程，并将该数据保存到表中。
这是XML输入
<root>
<table1 col1='a' col2='b'>
<table2Array>
<table2 col1='c' col2='d'>
<table3array>
<table3 col1='g' col2='h' />
<table3 col1='i' col2='j' />
</table3array>
</table2>
<table2 col1='c' col2='d'>
<table3array>
<table3 col1='k' col2='l' />
<table3 col1='i' col2='j' />
</table3array>
</table2>
</table2Array>
</table1>
<table1 col1='a' col2='b'>
<table2Array>
<table2 col1='e' col2='f'>
<table3array>
<table3 col1='i' col2='j' />
<table3 col1='i' col2='j' />
</table3array>
</table2>
<table2 col1='e' col2='f'>
<table3array>
<table3 col1='g' col2='h' />
<table3 col1='g' col2='h' />
</table3array>
</table2>
</table2Array>
</table1>
</root>
此xml来自第三方对象，我们无法控制修改第三方对象以发出不同格式的xml。
算法：
这是处理这种情况的唯一方法吗？如果是这样，如何遍历xml节点？
请帮助!!
谢谢，
也先
答案 0 :(得分：1)
使用merge和output，您可以使用here描述的技术在没有循环的情况下执行此操作。
我假设你的表结构是这样的。
create table Table1
(
Table1ID int identity primary key,
Col1 char(1),
Col2 char(1)
)
create table Table2
(
Table2ID int identity primary key,
Table1ID int references Table1(Table1ID),
Col1 char(1),
Col2 char(1)
)
create table Table3
(
Table3ID int identity primary key,
Table2ID int references Table2(Table2ID),
Col1 char(1),
Col2 char(1)
)
代码
declare @T1 table (XMLCol xml, TargetID int);
declare @T2 table (XMLCol xml, TargetID int);
merge Table1 as T
using (select T1.XMLCol.query('*'),
T1.XMLCol.value('@col1', 'char(1)'),
T1.XMLCol.value('@col2', 'char(1)')
from @XML.nodes('/root/table1') as T1(XMLCol)) as S(XMLCol, Col1, Col2)
on 1 = 0
when not matched then
insert (Col1, Col2) values (S.Col1, S.Col2)
output S.XMLCol, inserted.Table1ID into @T1;
merge Table2 as T
using (select T2.XMLCol.query('*'),
T1.TargetID,
T2.XMLCol.value('@col1', 'char(1)'),
T2.XMLCol.value('@col2', 'char(1)')
from @T1 as T1
cross apply T1.XMLCol.nodes('table2Array/table2') as T2(XMLCol)) as S(XMLCol, ID1, Col1, Col2)
on 1 = 0
when not matched then
insert (Table1ID, Col1, Col2) values (S.ID1, S.Col1, S.Col2)
output S.XMLCol, inserted.Table2ID into @T2;
insert into Table3(Table2ID, Col1, Col2)
select T2.TargetID,
T3.XMLCol.value('@col1', 'char(1)'),
T3.XMLCol.value('@col2', 'char(2)')
from @T2 as T2
cross apply T2.XMLCol.nodes('table3array/table3') as T3(XMLCol);
SE-Data（选择“仅文字结果”以查看所有结果集）
答案 1 :(得分：0)
如果您的代码示例代表了您获得的数据类型，并且严格遵循一致的结构，那么您可以尝试创建一个反序列化的类。下面是一组示例，它们将从您给定的XML示例中正确反序列化：
[XmlRoot("root")]
public class MyCustomStructure
{
[XmlElement("table1")]
public Table1Structure[] Table1Array { get; set; }
}
[XmlRoot("table1")]
public class Table1Structure
{
[XmlAttribute("col1")]
public string Col1 { get; set; }
[XmlAttribute("col2")]
public string Col2 { get; set; }
[XmlArray("table2Array")]
[XmlArrayItem("table2")]
public Table2Structure[] Table2Array { get; set; }
}
[XmlRoot("table2")]
public class Table2Structure
{
[XmlAttribute("col1")]
public string Col1 { get; set; }
[XmlAttribute("col2")]
public string Col2 { get; set; }
[XmlArray("table3array")]
[XmlArrayItem("table3")]
public Table3Structure[] Table3Array { get; set; }
}
public class Table3Structure
{
[XmlAttribute("col1")]
public string Col1 { get; set; }
[XmlAttribute("col2")]
public string Col2 { get; set; }
}
将应用反序列化的示例代码：
var ser = new XmlSerializer(typeof(MyCustomStructure));
// if xml is in a string, use the following:
var sr = new StringReader(xml);
var xr = new XmlTextReader(sr);
// if xml is in a stream, use the following:
var xr = new XmlTextReader(stream);
// if xml is in an XmlElement, use the following:
var xr = new XmlNodeReader(element);
// result contains an instance of MyCustomStructure
var result = ser.Deserialize(xr);
从这里开始，就像为每个循环循环遍历MyCustomStructure的内容并应用自定义数据库插入逻辑一样简单：
for each (var table1 in result.Table1Array)
{
// insert table1, get inserted ID
for each (var table2 in table1.Table2Array)
{
// insert table2, use table1 inserted ID, get table2 ID
for each (var table3 in table2.Table3Array)
{
// insert table3, use table2 inserted ID
}
}
}
如果您担心要插入的数据规模的性能，您可以尝试将数据作为表值参数传递，或者您可以在SQL端轻松解析的其他格式。您还可以批量上传所有table1条目，获取所有ID，然后使用正确的映射ID批量上传所有table2条目，获取所有新ID，等等，这将需要总共3次左右的往返而且应该很快。
答案 2 :(得分：0)
认为对寻找类似解决方案的人有帮助。这就是我在SQL中处理遍历节点的方法
declare @xmlRoot as xml
set @xmlRoot= '<root>
<table1 col1="a" col2="b">
<table2Array>
<table2 col1="c" col2="d">
<table3array>
<table3 col1="g" col2="h" />
<table3 col1="i" col2="j" />
</table3array>
</table2>
<table2 col1="c" col2="d">
<table3array>
<table3 col1="k" col2="l" />
<table3 col1="i" col2="j" />
</table3array>
</table2>
</table2Array>
</table1>
<table1 col1="a" col2="b">
<table2Array>
<table2 col1="e" col2="f">
<table3array>
<table3 col1="i" col2="j" />
<table3 col1="i" col2="j" />
</table3array>
</table2>
<table2 col1="e" col2="f">
<table3array>
<table3 col1="g" col2="h" />
<table3 col1="g" col2="h" />
</table3array>
</table2>
</table2Array>
</table1>
</root>'
Declare @col1 varchar(100),@col2 varchar(100), @table1Counter int, @table2Counter int
select @table1Counter=0
DECLARE table1_cursor CURSOR FOR
SELECT
col1 = item.value('./@col1', 'varchar(100)'),
col2 = item.value('./@col2', 'varchar(100)')
FROM @xmlRoot.nodes('root/table1') AS T(item);
OPEN table1_cursor
FETCH NEXT FROM table1_cursor
INTO @col1 ,@col2
WHILE @@FETCH_STATUS = 0
BEGIN
--insert into table1 and get id into a variable
set @table1Counter=@table1Counter+1
DECLARE table2_cursor CURSOR FOR
SELECT
col1 = item.value('./@col1', 'varchar(100)'),
col2 = item.value('./@col2', 'varchar(100)')
FROM @xmlRoot.nodes('root/table1[sql:variable("@table1Counter")]/table2Array/table2') AS T(item);
OPEN table2_cursor
FETCH NEXT FROM table2_cursor INTO @col1 ,@col2
WHILE @@FETCH_STATUS = 0
BEGIN
--insert into table2 and get id into a varialbe
set @table2Counter = @table2Counter+1
--do same for table3 similar to table2
FETCH NEXT FROM table2_cursor INTO @col1 ,@col2
END
CLOSE table2_cursor
DEALLOCATE table2_cursor
FETCH NEXT FROM table1_cursor
INTO @col1, @col2
END
CLOSE table1_cursor;
DEALLOCATE table1_cursor;