现在使用数据库来写存储过程，动不动参数就会用到xml ，当然罗，优势也很明显，参数相对固定，而且灵活，如果要修改或者什么的，中间接口层也不需要做变化，只需要修改封装的存储过程以及程序传参就ok了。
随着时间慢慢过，有时候就有一个存储过程，一个xml 来应对整个表的新增，修改，删除的情况了。而对于这个情况，我个人比较喜欢使用 Merge关键字来处理。但是如果表里面的列很多，那么复制黏贴啊之类的机械动作就会很多，而且没有什么价值。所以我就写了一个小脚本，应对了使用xml 来做表的增删改的作用
首先我先创建一个表
CREATE TABLE employee(
ID INT IDENTITY(1,1) PRIMARY KEY,
name NVARCHAR(50),
age INT,
birthdate DATE,
salary MONEY
)
然后我准备使用这个xml 来进行对应写入
DECLARE @employee XML='
<root>
<employee Action="1"> <!--这个Action 代表动作，1 新增 2 修改 3 删除 这样来控制比较灵活，不需要每次都一大段-->
<name>AAA</name>
<age>27</age>
<birthdate>1989-01-02</birthdate>
<salary>1200</salary>
</employee>
<employee Action="1">
<name>BBB</name>
<age>23</age>
<birthdate>1994-01-02</birthdate>
<salary>2200</salary>
</employee>
</root>
'
然后是生成的脚本。通常解析xml 会有2种的解析方法，一种是直接用openxml 来进行解析，一种是使用 xml.nodes 的函数进行取值，这里我两种都可以进行一个简单处理生成
DECLARE @TableName VARCHAR(50) = 'employee',
@XMLType TINYINT = 1, --1 使用with 格式, 2 使用nodes 格式
@Path NVARCHAR(max) = 'root/employee',
@HasAction BIT = 1 --0 没有动作 1 包含动作 DECLARE @Columns NVARCHAR(MAX), --通用列的串
@FilterColumns NVARCHAR(max), --过滤外键，主键的列
@On NVARCHAR(100), --自动生成主键去匹配
@Sql NVARCHAR(MAX) SELECT @Columns = STUFF((
SELECT ',' + name
FROM sys.columns
WHERE object_id = OBJECT_ID(@TableName)
ORDER BY column_id
FOR XML PATH('')),1,1,''),
@FilterColumns = STUFF((
SELECT ',' + name
FROM sys.columns
WHERE object_id = OBJECT_ID(@TableName)
AND is_computed = 0
AND is_identity = 0
ORDER BY column_id
FOR XML PATH('')),1,1,''),
@On = STUFF((
SELECT 'AND TAR.' + c.name + ' = SOUR.' + c.name
FROM sys.indexes a
INNER JOIN sys.index_columns b ON a.object_id = b.object_id
INNER JOIN sys.columns c ON c.object_id = b.object_id AND b.column_id = c.column_id
WHERE a.object_id = OBJECT_ID(@TableName)
AND a.is_primary_key = 1),1,4,'') SELECT @Sql = ';WITH SOUR AS(
SELECT '+ CASE WHEN @XMLType = 1 THEN REPLACE(@Columns ,',',CHAR(10) + REPLICATE(CHAR(9),2) + ',')
WHEN @XMLType = 2 THEN STUFF((SELECT CHAR(10) + ',t.c.value(''(' + a.name + '/text())[1]'',''' + TYPE_NAME(user_type_id) + CASE WHEN a.system_type_id IN (167,175) THEN '(' + CASE WHEN a.max_length = -1 THEN 'max' ELSE RTRIM(a.max_length) END+ ')'
WHEN a.system_type_id IN (231,239) THEN '(' + CASE WHEN a.max_length = -1 THEN 'max' ELSE RTRIM(a.max_length/2) END + ')'
WHEN a.system_type_id IN (59,106,108) THEN '(' + RTRIM(a.max_length) + ',' + RTRIM(a.scale) + ')'
ELSE ''
END + ''') AS ' + a.name
FROM sys.columns a
WHERE object_id = OBJECT_ID(@TableName)
ORDER BY column_id
FOR XML PATH('')),1,2,'')
ELSE '' END
+ CASE WHEN @XMLType = 1 AND @HasAction = 1 THEN CHAR(10)+ REPLICATE(CHAR(9),2) + ',[Action]'
WHEN @XMLType = 2 AND @HasAction = 1 THEN CHAR(10)+ REPLICATE(CHAR(9),2) + ',t.c.value(''@Action'',''tinyint'') [Action]'
ELSE '' END
+ '
FROM ' + CASE @XMLType WHEN 1 THEN ' OPENXML(@XmlInt,''' + @Path + ''',3)
WITH(' + STUFF((SELECT CHAR(10)+ REPLICATE(CHAR(9),6) + ',' + a.name + ' ' + UPPER(b.name) + CASE WHEN a.system_type_id IN (167,175,231,239,108) THEN '(' + CASE WHEN a.max_length = -1 THEN 'MAX' ELSE RTRIM(a.max_length) END + ')'
WHEN a.system_type_id IN (59,106,108) THEN '(' + RTRIM(a.precision) + ',' + RTRIM(a.scale)+ ')'
ELSE '' END + ' ''' + a.name + ''''
FROM sys.columns a
INNER JOIN sys.systypes b ON a.system_type_id = b.xtype AND b.status = 0
WHERE object_id = OBJECT_ID(@TableName)
AND a.is_computed = 0
ORDER BY column_id
FOR XML PATH ('')
),1,8,'') +
+ CASE WHEN @HasAction = 1 THEN CHAR(10)+ REPLICATE(CHAR(9),6) + ',[Action] tinyint ''@Action'')' ELSE ')' END
WHEN 2 THEN ' @' + @TableName + '.nodes('''+@Path+''') as t(c)'
ELSE '' END
+ '),
TAR AS( SELECT ' + REPLACE(@Columns,',',CHAR(10) + REPLICATE(CHAR(9),2) + ',') + '
FROM ' + @TableName + ')
MERGE TAR
USING SOUR
ON '+@On+'
WHEN NOT MATCHED ' + CASE WHEN @HasAction = 1 THEN ' AND SOUR.[Action] = 1 ' ELSE '' END + '
THEN INSERT(' + @FilterColumns + ')' + CHAR(10) + REPLICATE(CHAR(9),5) + ' VALUES (SOUR.' + REPLACE(@FilterColumns,',',',SOUR.') + ')
WHEN MATCHED ' + CASE WHEN @HasAction = 1 THEN ' AND SOUR.[Action] = 2 ' ELSE '' END + ' THEN UPDATE SET '
+ STUFF(( SELECT ',' + CHAR(10) + REPLICATE(CHAR(9),5) + 'TAR.[' + name + ']= SOUR.[' + name + ']'
FROM sys.columns a
WHERE object_id = OBJECT_ID(@TableName)
AND is_computed = 0
AND is_identity = 0
AND NOT EXISTS(SELECT * FROM sys.foreign_key_columns WHERE parent_object_id = a.object_id AND parent_column_id = a.column_id)
ORDER BY column_id
FOR XML PATH('')
),1,6,'') + '
'+ CASE WHEN @HasAction = 1 THEN ' WHEN MATCHED AND SOUR.[Action] = 3 ' ELSE
'WHEN MATCHED BY SOURCE ' END + ' THEN Delete;'
PRINT @Sql
(因为偷懒，所以使用的openxml 里面的那个 sp_xml_preparedocument 这里我是没有写的)(*^__^*) 嘻嘻……
然后看下生成的情况，这个是使用xml.nodes 来生成的
;WITH SOUR AS(
SELECT t.c.value('(ID/text())[1]','int') AS ID
,t.c.value('(name/text())[1]','nvarchar(50)') AS name
,t.c.value('(age/text())[1]','int') AS age
,t.c.value('(birthdate/text())[1]','date') AS birthdate
,t.c.value('(salary/text())[1]','money') AS salary
,t.c.value('@Action','tinyint') [Action]
FROM @employee.nodes('root/employee') as t(c)),
TAR AS( SELECT ID
,name
,age
,birthdate
,salary
FROM employee)
MERGE TAR
USING SOUR
ON TAR.ID = SOUR.ID
WHEN NOT MATCHED AND SOUR.[Action] = 1
THEN INSERT(name,age,birthdate,salary)
VALUES (SOUR.name,SOUR.age,SOUR.birthdate,SOUR.salary)
WHEN MATCHED AND SOUR.[Action] = 2 THEN UPDATE SET TAR.[name]= SOUR.[name],
TAR.[age]= SOUR.[age],
TAR.[birthdate]= SOUR.[birthdate],
TAR.[salary]= SOUR.[salary]
WHEN MATCHED AND SOUR.[Action] = 3 THEN Delete;
xml.nodes
这个是使用openxml来生成的
;WITH SOUR AS(
SELECT ID
,name
,age
,birthdate
,salary
,[Action]
FROM OPENXML(@XmlInt,'root/employee',3)
WITH(ID INT 'ID'
,name NVARCHAR(100) 'name'
,age INT 'age'
,birthdate DATE 'birthdate'
,salary MONEY 'salary'
,[Action] tinyint '@Action')),
TAR AS( SELECT ID
,name
,age
,birthdate
,salary
FROM employee)
MERGE TAR
USING SOUR
ON TAR.ID = SOUR.ID
WHEN NOT MATCHED AND SOUR.[Action] = 1
THEN INSERT(name,age,birthdate,salary)
VALUES (SOUR.name,SOUR.age,SOUR.birthdate,SOUR.salary)
WHEN MATCHED AND SOUR.[Action] = 2 THEN UPDATE SET TAR.[name]= SOUR.[name],
TAR.[age]= SOUR.[age],
TAR.[birthdate]= SOUR.[birthdate],
TAR.[salary]= SOUR.[salary]
WHEN MATCHED AND SOUR.[Action] = 3 THEN Delete;
openxml
恩~然后就可放进去执行啦~~
这里只是一个很基本的用法。有几点要说明的
1、Xml的名称我默认和表名一致，有需要请改动
2、On的匹配模型我是使用主键来进行对应
其它如果有什么问题请告诉我补充~