使用一个存储过程完成数据插入和更新（使用xml）（通用insert和update）(mssql2008以上)
天天维护网站，天天写数据插入insert into。。。。天天写数据更新update .. set 。。。。而且每个页面，每个表，每个数据的结构都不太一样，即便是同一个表，应用不同，应用到的列也不一样，每次都重新写sql指令，好烦躁
于是，琢磨了一下，可不可以用一个存储过程自动完成数据插入和更新呢？
首先，应该把所有应用到的字段整理一下，作为参数传递给存储过程，比如：id,name,col,sort,desc,xxtime等等等等。。。
好吧，参数就这么麻烦，得了，把他们封装到一起吧，想想看，sql2008已经有不少关于xml的处理方法和函数了，那么，直接把所有参数封装到一个xml里，参数传递的问题就解决了，嗯。。。这个思路不错，这样，我们就传递“
然后，我们先创建一个测试用的存储过程
CREATE PROCEDURE test_update_with_xml
@args xml
AS
BEGIN
SET NOCOUNT ON;
declare @handle int,@prepare int
exec @prepare = sp_xml_preparedocument @handle output,@args
;with t as (
select * from openxml(@handle,'/r',1)
),t1 as (
select a.id as rowid,a.localname as col,convert(nvarchar(max),b.text) as val
from t a
left join t as b on b.parentid=a.id
where a.parentid=0
)
select * from t1
END嗯。。。。测试一下，还可以，能得到一个返回的表，这个表里就是我们传入的xml的内容了，并且列和值也分开了
那么，我们继续第三步：保证数据的完整性
因为有很多时候，我们为了保证数据的完整，在创建表结构的时候，我们就设置了一些字段不允许为空，而有些时候，我们则设置了默认值，那么，对于我们的参数传递进来的，没有涉及到的字段未必是不需要的，所以，我们还得把目标表结构掉出来，并进行补足
好吧，上边这个第三步是为了插入数据准备的，判断依据则很简单，有主键字段的，则是更新，否则是插入
更新指令比较简单，因为数据行已存在，不存在插入失败的情况，所以我们先把更新弄出来
declare @handle int,@prepare int
exec @prepare = sp_xml_preparedocument @handle output,@args
;with t as (
select * from openxml(@handle,'/r',1)
),t1 as (
select a.id as rowid,a.localname as col,convert(nvarchar(max),b.text) as val
from t a
left join t as b on b.parentid=a.id
where a.parentid=0
)
select * into #t from t1
declare @id int
select @id = val from #t where col='id'
if isnull(@id,0)=0
begin
-- 数据插入
end
else
begin
-- 数据更新
end那么，我们现在就把需要更新的字段信息补全，生成临时表#t1
declare @tbid int,@tbname varchar(100)
select @tbname='测试用的表名'
select @tbid = id from sysobjects with (nolock) where name=@tbname
select a.col,a.val,b.colorder,isnullable,s.text as def,t.name as coltype
into #t1
from #t a
left join syscolumns b with (nolock) on a.col=b.name and b.id=@tbid
left join syscomments s with (nolock) on b.cdefault=s.id
left join systypes t with (nolock) on b.xtype=t.xusertype
再然后就是拼接字符串，生成update指令了，由于不确定到底更新哪些字段，所以，我们使用游标来协助一下
declare cur cursor local for
select col,(case
when val is not null then (case
when charindex('char',coltype)>0 then ''''+replace(val,'''','''''')+''''
when coltype in ('date','datetime','uniqueidentifier') then ''''+val+''''
else val
end)
when def is not null then def
when isnullable=0 then (case
when charindex('char',coltype)>0 then ''''''
when coltype in ('int','bigint','money','bit','decimal','float') then '0'
when coltype in ('date','datetime') then 'getdate()'
when coltype='uniqueidentifier' then ''''+convert(varchar(50),newid())+''''
end)
else 'null'
end) as val
from #t1 where col<>'p_id' and colorder is not null
order by colorder
因为在临时表t1里，我们已经把是否允许为空，默认值都搞出来了，所以，在游标里，我们直接把这些都弄好，直接弄成可以用来拼接字符串的值，比如varchar类型的，就把值里的所有单引号进行转义替换，并且外边加上引号
那么更新指令就很简单的可以得到了
open cur
declare @sql nvarchar(max)
set @sql = 'update '+@tbname+' set somefield=''somevalue''' -- 这里根据需要写一些默认的字段，如果没有的话，下边的@sql就把逗号放到最后
fetch next from cur into @col,@val
while @@fetch_status=0
begin
-- 如果没有默认需要更新的字段，逗号放在后边set @sql = @sql+@col+'='+@val +','
set @sql = @sql +','+@col+'='+@val
fetch next from cur into @col,@val
end
-- 如果逗号放在后边，需要去除最后的逗号
set @sql = @sql + ' where p_id='+convert(varchar,@pid)
exec(@sql)
close cur
deallocate cur
嗯，还不错，更新指令可以说完美的生成出来了
那么，我们现在来弄一弄插入指令
插入比更新麻烦的地方在于，更新，我们只需要匹配出表结构对应的字段即可，及以临时表#t为主要依据，但是插入数据的话，我们需要以syscolumns为主要依据，以避免出现遗漏的非空字段遗漏，造成插入失败的问题
那么，我们重新来写一个生成临时表的方法，用来生成插入字段
;with t as (
select * from openxml(@handle,'/r',1)
),t1 as (
select a.id as rowid,a.localname as col,convert(nvarchar(max),b.text) as val
from t a
left join t as b on b.parentid=a.id
where a.parentid=0
)
select isnull(col,b.name) as col,a.val,b.colorder,isnullable,b.def,b.coltype
into #t2
from t1 a
full outer join (
select b.name,colorder,isnullable,s.text as def,t.name as coltype from syscolumns b with (nolock)
left join syscomments s with (nolock) on b.cdefault=s.id
left join systypes t with (nolock) on b.xtype=t.xusertype
where b.id=@tbid
-- 对一些入库时不会涉及的字段，且允许为空，或者有默认值的，可以进行排除
and b.name not in ('id','sn','state','isdel','oauth','p_create','detail_time')
) b on a.col=b.name
嗯，这个临时表t2的内容就比之前的t1多了不少东西，后边也就简单了，还是使用游标，然后生成插入指令
declare cur cursor local for
select col,(case
when val is not null then (case
when charindex('char',coltype)>0 then ''''+replace(val,'''','''''')+''''
when coltype in ('date','datetime','uniqueidentifier') then ''''+val+''''
else val
end)
when def is not null then def
when isnullable=0 then (case
when charindex('char',coltype)>0 then ''''''
when coltype in ('int','bigint','money','bit','decimal','float') then '0'
when coltype in ('date','datetime') then 'getdate()'
when coltype='uniqueidentifier' then ''''+convert(varchar(50),newid())+''''
end)
else 'null'
end) as val
from #t2 where col<>'主键字段名' and colorder is not null
order by colorder
open cur
set @sql = 'insert into ' + @tbname + '([fields]) values([values])'
fetch next from cur into @col,@val
while @@fetch_status=0
begin
set @sql = replace(@sql,',[fields]',','+@col+',[fields]')
set @sql = replace(@sql,',[values]',','+@val+',[values]')
fetch next from cur into @col,@val
end
set @sql = replace(@sql,',[fields]','')
set @sql = replace(@sql,',[values]','')
exec(@sql)
close cur
deallocate cur
嗯，这个貌似也不错，可以用了
好吧，这样一来就很简单了，我们将这个内容调整一下，就可以做出一个通用的存储过程，对单表内容进行插入和更新了
下边就是完整的存储过程
CREATE PROCEDURE InsertOrUpdate
@args xml,@tbname varchar(100)
AS
BEGIN
SET NOCOUNT ON;
declare @handle int,@prepare int,@tbid int,@pk varchar(100)
exec @prepare = sp_xml_preparedocument @handle output,@args
-- 获得表id
select @tbid = id from sysobjects with (nolock) where name=@tbname
-- 获得主键字段名
select @pk=c.name
from sysindexes i with (nolock)
inner join sysindexkeys k with (nolock) on i.id=k.id and i.indid=k.indid
inner join sysobjects o with (nolock) on o.parent_obj=i.id and o.xtype='pk' and o.name=i.name
inner join syscolumns c with (nolock) on c.id=k.id and c.colid=k.colid
where i.id=@tbid
-- 解析xml到临时表#t
;with t as (
select * from openxml(@handle,'/r',1)
),t1 as (
select a.id as rowid,a.localname as col,convert(nvarchar(max),b.text) as val
from t a
left join t as b on b.parentid=a.id
where a.parentid=0
)
select a.col,a.val,b.colorder,isnullable,s.text as def,t.name as coltype
into #t
from t1 a
left join syscolumns b with (nolock) on a.col=b.name and b.id=@tbid
left join syscomments s with (nolock) on b.cdefault=s.id
left join systypes t with (nolock) on b.xtype=t.xusertype
declare @id int,@sql nvarchar(max),@col varchar(50),@val nvarchar(max)
-- 获得主键值
select @id = val from #t where col=@pk
if isnull(@id,0)=0
begin
-- 如果主键为0，则重新整理生成需要插入字段集合的临时表
delete from #t
;with t as (
select * from openxml(@handle,'/r',1)
),t1 as (
select a.id as rowid,a.localname as col,convert(nvarchar(max),b.text) as val
from t a
left join t as b on b.parentid=a.id
where a.parentid=0
)
insert into #t
select isnull(col,b.name) as col,a.val,b.colorder,isnullable,b.def,b.coltype
from t1 a
full outer join (
select b.name,colorder,isnullable,s.text as def,t.name as coltype from syscolumns b with (nolock)
left join syscomments s with (nolock) on b.cdefault=s.id
left join systypes t with (nolock) on b.xtype=t.xusertype
where b.id=@tbid
and b.name not in (@pk)
) b on a.col=b.name
where a.col is not null or (isnullable=0 and def is null)
end
declare cur cursor local for
select col,(case
when val is not null then (case
when charindex('char',coltype)>0 then ''''+replace(val,'''','''''')+''''
when coltype in ('date','datetime','uniqueidentifier') then ''''+val+''''
else val
end)
when def is not null then def
when isnullable=0 then (case
when charindex('char',coltype)>0 then ''''''
when coltype in ('int','bigint','money','bit','decimal','float') then '0'
when coltype in ('date','datetime') then 'getdate()'
when coltype='uniqueidentifier' then ''''+convert(varchar(50),newid())+''''
end)
else 'null'
end) as val
from #t where col<>@pk and colorder is not null
order by colorder
open cur
if @id>0
begin
set @sql = 'update ' + @tbname + ' set '
fetch next from cur into @col,@val
while @@fetch_status=0
begin
set @sql = @sql + '[' + @col + ']' + '=' + @val +','
fetch next from cur into @col,@val
end
set @sql = stuff(@sql,len(@sql),1,'')
set @sql = @sql + ' where ' + @pk + '='+convert(varchar,@id)
select @sql
--exec(@sql)
end
else
begin
set @sql = 'insert into ' + @tbname + '('+@pk+',[fields]) values('+@pk+',[values]);select @id = scope_identity()'
fetch next from cur into @col,@val
while @@fetch_status=0
begin
set @sql = replace(@sql,',[fields]',','+@col+',[fields]')
set @sql = replace(@sql,',[values]',','+@val+',[values]')
fetch next from cur into @col,@val
end
set @sql = replace(@sql,',[fields]','')
set @sql = replace(@sql,',[values]','')
set @sql = replace(@sql,'('+@pk+',','(')
select @sql
--exec sp_executesql @sql,N'@id int output',@id=@id output
end
close cur
deallocate cur
select @id
drop table #t
END
当然了，这个存储过程仅仅是用来更新或插入一个单表数据的，而实际应用中，我们经常同时更新多个表的内容，毕竟有些字段我们会放到相关的关联表中，那么，针对这种情况，我们只需要再写一个特定的存储过程，同样还是将xml传递进来，然后进行分发即可，例如
CREATE PROCEDURE update_product
@args xml
AS
BEGIN
SET NOCOUNT ON;
exec dbo.InsertOrUpdate @args,'table_product'
exec dbo.InsertOrUpdate @args,'table_product_images'
END至于分发到各个表的内容，根据需要自己整理一下即可，反正 for xml 方法别的介绍文章也是一大片了