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
1 DECLARE @TableName VARCHAR(50) = 'employee', 2 @XMLType TINYINT = 1, --1 使用with 格式, 2 使用nodes 格式 3 @Path NVARCHAR(max) = 'root/employee', 4 @HasAction BIT = 1 --0 没有动作 1 包含动作 5 6 DECLARE @Columns NVARCHAR(MAX), --通用列的串 7 @FilterColumns NVARCHAR(max), --过滤外键，主键的列 8 @On NVARCHAR(100), --自动生成主键去匹配 9 @Sql NVARCHAR(MAX) 10 11 SELECT @Columns = STUFF(( 12 SELECT ',' + name 13 FROM sys.columns 14 WHERE object_id = OBJECT_ID(@TableName) 15 ORDER BY column_id 16 FOR XML PATH('')),1,1,''), 17 @FilterColumns = STUFF(( 18 SELECT ',' + name 19 FROM sys.columns 20 WHERE object_id = OBJECT_ID(@TableName) 21 AND is_computed = 0 22 AND is_identity = 0 23 ORDER BY column_id 24 FOR XML PATH('')),1,1,''), 25 @On = STUFF(( 26 SELECT 'AND TAR.' + c.name + ' = SOUR.' + c.name 27 FROM sys.indexes a 28 INNER JOIN sys.index_columns b ON a.object_id = b.object_id 29 INNER JOIN sys.columns c ON c.object_id = b.object_id AND b.column_id = c.column_id 30 WHERE a.object_id = OBJECT_ID(@TableName) 31 AND a.is_primary_key = 1),1,4,'') 32 33 34 35 SELECT @Sql = ';WITH SOUR AS( 36 SELECT '+ CASE WHEN @XMLType = 1 THEN REPLACE(@Columns ,',',CHAR(10) + REPLICATE(CHAR(9),2) + ',') 37 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+ ')' 38 WHEN a.system_type_id IN (231,239) THEN '(' + CASE WHEN a.max_length = -1 THEN 'max' ELSE RTRIM(a.max_length/2) END + ')' 39 WHEN a.system_type_id IN (59,106,108) THEN '(' + RTRIM(a.max_length) + ',' + RTRIM(a.scale) + ')' 40 ELSE '' 41 END + ''') AS ' + a.name 42 FROM sys.columns a 43 WHERE object_id = OBJECT_ID(@TableName) 44 ORDER BY column_id 45 FOR XML PATH('')),1,2,'') 46 ELSE '' END 47 + CASE WHEN @XMLType = 1 AND @HasAction = 1 THEN CHAR(10)+ REPLICATE(CHAR(9),2) + ',[Action]' 48 WHEN @XMLType = 2 AND @HasAction = 1 THEN CHAR(10)+ REPLICATE(CHAR(9),2) + ',t.c.value(''@Action'',''tinyint'') [Action]' 49 ELSE '' END 50 + ' 51 FROM ' + CASE @XMLType WHEN 1 THEN ' OPENXML(@XmlInt,''' + @Path + ''',3) 52 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 + ')' 53 WHEN a.system_type_id IN (59,106,108) THEN '(' + RTRIM(a.precision) + ',' + RTRIM(a.scale)+ ')' 54 ELSE '' END + ' ''' + a.name + '''' 55 FROM sys.columns a 56 INNER JOIN sys.systypes b ON a.system_type_id = b.xtype AND b.status = 0 57 WHERE object_id = OBJECT_ID(@TableName) 58 AND a.is_computed = 0 59 ORDER BY column_id 60 FOR XML PATH ('') 61 ),1,8,'') + 62 + CASE WHEN @HasAction = 1 THEN CHAR(10)+ REPLICATE(CHAR(9),6) + ',[Action] tinyint ''@Action'')' ELSE ')' END 63 WHEN 2 THEN ' @' + @TableName + '.nodes('''+@Path+''') as t(c)' 64 ELSE '' END 65 + '), 66 TAR AS( SELECT ' + REPLACE(@Columns,',',CHAR(10) + REPLICATE(CHAR(9),2) + ',') + ' 67 FROM ' + @TableName + ') 68 MERGE TAR 69 USING SOUR 70 ON '+@On+' 71 WHEN NOT MATCHED ' + CASE WHEN @HasAction = 1 THEN ' AND SOUR.[Action] = 1 ' ELSE '' END + ' 72 THEN INSERT(' + @FilterColumns + ')' + CHAR(10) + REPLICATE(CHAR(9),5) + ' VALUES (SOUR.' + REPLACE(@FilterColumns,',',',SOUR.') + ') 73 WHEN MATCHED ' + CASE WHEN @HasAction = 1 THEN ' AND SOUR.[Action] = 2 ' ELSE '' END + ' THEN UPDATE SET ' 74 + STUFF(( SELECT ',' + CHAR(10) + REPLICATE(CHAR(9),5) + 'TAR.[' + name + ']= SOUR.[' + name + ']' 75 FROM sys.columns a 76 WHERE object_id = OBJECT_ID(@TableName) 77 AND is_computed = 0 78 AND is_identity = 0 79 AND NOT EXISTS(SELECT * FROM sys.foreign_key_columns WHERE parent_object_id = a.object_id AND parent_column_id = a.column_id) 80 ORDER BY column_id 81 FOR XML PATH('') 82 ),1,6,'') + ' 83 '+ CASE WHEN @HasAction = 1 THEN ' WHEN MATCHED AND SOUR.[Action] = 3 ' ELSE 84 'WHEN MATCHED BY SOURCE ' END + ' THEN Delete;' 85 PRINT @Sql