我有一些应用程序的属性以XML格式传递给我。我需要按名称解析属性,并将值分配给我的数据库中的相应列。
我目前正在SSIS脚本组件中解析它,但它需要很长时间才能完成。我希望使用XQUERY有一个简单的解决方案,但我找不到我要找的东西。
以下是我收到的xml示例:
<properties>
<property>
<name>DISMISS_SETTING</name>
<value>DEFAULT</value>
</property>
<property>
<name>SHOW_SETTING</name>
<value>DEFAULT</value>
</property>
<property>
<name>DEFAULT_SETTING</name>
<value>DEFAULT</value>
</property>
</properties>
所以,如果我查看第一个属性元素,我会将值DEFAULT分配给我的数据库中的DISMISS_SETTING列。此外,重要的是要注意,值的顺序和组合可能没有特定的顺序。
答案 0 :(得分:9)
使用value() Method (xml Data Type)从XML中提取值。在XQuery表达式中检查谓词中所需的名称。
select
@XML.value('(/properties/property[name = "DISMISS_SETTING"]/value/text())[1]', 'nvarchar(100)') as DISMISS_SETTING,
@XML.value('(/properties/property[name = "SHOW_SETTING"]/value/text())[1]', 'nvarchar(100)') as SHOW_SETTING,
@XML.value('(/properties/property[name = "DEFAULT_SETTING"]/value/text())[1]', 'nvarchar(100)') as DEFAULT_SETTING
答案 1 :(得分:1)
如果您正在寻找TSQL解决方案,并且我的结果表看起来如下所示:
| DISMISS_SETTING | SHOW_SETTING | DEFAULT_SETTING |
|-----------------|--------------|-----------------|
| DEFAULT | DEFAULT | DEFAULT |
你应该使用我稍后将描述的一组脚本。最初,您需要创建动态查询的动态存储过程 - 它使您可以在这些列下将数据插入到表中,这些列在运行时(XML解析的时间)之前是未知的:
create procedure mysp_update (@table_name nvarchar(50), @column_name nvarchar(50), @column_value nvarchar(50))
as
begin
declare @rows_count int
declare @query nvarchar(500)
declare @parm_definition nvarchar(100)
-- Get rows count in your table using sp_executesql and an output parameter
set @query = N'select @rows_count = count(1) from ' + quotename(@table_name)
exec sp_executesql @query, N'@rows_count INT OUTPUT', @rows_count OUTPUT
-- If no rows - insert the first one, else - update existing
if @rows_count = 0
set @query = N'insert into ' + quotename(@table_name) + N'(' + quotename(@column_name) + N') values (@column_value)'
else
set @query = N'update ' + quotename(@table_name) + N'set ' + quotename(@column_name) + N' = @column_value'
set @parm_definition = N'@column_value nvarchar(50)'
exec sp_executesql @query, @parm_definition, @column_value = @column_value
end
go
接下来,使用此XQuery / SQL语句从您正在寻找的信息中提取(来自XML):
-- Define XML object based on which insert statement will be later created
declare @data xml = N'<properties>
<property>
<name>DISMISS_SETTING</name>
<value>DEFAULT</value>
</property>
<property>
<name>SHOW_SETTING</name>
<value>DEFAULT</value>
</property>
<property>
<name>DEFAULT_SETTING</name>
<value>DEFAULT</value>
</property>
</properties>'
-- Declare temporary container
declare @T table(id int identity, name nvarchar(50), value nvarchar(50))
-- Push the extracted nodes values into it
insert into @T(name, value)
select
x.value(N'(name)[1]', N'nvarchar(50)'),
x.value(N'(value)[1]', N'nvarchar(50)')
from
@data.nodes(N'/properties/property') AS XTbl(x)
之后,提取的数据对 [name,value] 存储在表变量@T
中。最后,迭代这些临时元数据并在主表的相应列名中插入值:
declare @name nvarchar(50), @value nvarchar(50), @current_id int = 1
-- Fetch first row
select @name = name, @value = value
from @T where id = @current_id
while @@rowcount = 1
begin
-- Execute SP here (btw: SP cannot be executed from select statement)
exec mysp_update N'TableName', @name, @value
-- Fetch next row
set @current_id = @current_id + 1
select @name = name, @value = value
from @T where id = @current_id
end
提供的解决方案允许您在XML中拥有可变数量的节点,无需任何特定顺序。
请注意,负责从XML提取数据和插入主表的逻辑可以包含在附加的存储过程中,例如: mysp_xml_update (@data xml)
然后以干净的方式执行:exec mysp_xml_update N'<properties>....</properties>
。
尽管如此,请使用SQL Fiddle自行尝试代码。
<强>更新强>
根据评论中的要求 - 应该执行一个大的更新,而不是按列顺序更新。为此,mysp_update
应该被修改,例如以下方式:
create type HashTable as table(name nvarchar(50), value nvarchar(50))
go
create procedure mysp_update (@table_name nvarchar(50), @set HashTable readonly)
as
begin
-- Concatenate names and values (to be passed to insert statement below)
declare @columns varchar(max)
select @columns = COALESCE(@columns + ', ', '') + quotename(name) from @set
declare @values varchar(max)
select @values = COALESCE(@values + ', ', '') + quotename(value, '''') from @set
-- Remove previous values
declare @query nvarchar(500)
set @query = N'delete from ' + quotename(@table_name)
-- Insert new values to the table
exec sp_executesql @query
set @query = N'insert into ' + quotename(@table_name) + N'(' + @columns + N') values (' + @values + N')'
exec sp_executesql @query
end
go
答案 2 :(得分:1)
您可以通过从xml中提取名称和值并围绕名称进行旋转来完成此操作。但是,您无法使用查询时找到的任意名称执行此操作。如果您需要,最好不要删除PIVOT,只使用内部查询提供的名称和值列。
DECLARE @xml xml
SET @xml = N'<properties>
<property>
<name>DISMISS_SETTING</name>
<value>DEFAULT</value>
</property>
<property>
<name>SHOW_SETTING</name>
<value>DEFAULT</value>
</property>
<property>
<name>DEFAULT_SETTING</name>
<value>DEFAULT</value>
</property>
</properties>'
SELECT [DISMISS_SETTING], [SHOW_SETTING], [DEFAULT_SETTING]
FROM (
SELECT properties.property.value(N'./name[1]', N'nvarchar(MAX)') AS propertyName
, properties.property.value(N'./value[1]', N'nvarchar(MAX)') AS propertyValue
FROM @xml.nodes(N'/properties/property') AS properties(property)
) AS properties
PIVOT (MIN(propertyValue) FOR propertyName IN ([DISMISS_SETTING], [SHOW_SETTING], [DEFAULT_SETTING])) AS settings
答案 3 :(得分:1)
我决定更新我现有的答案(只是为了好奇的替代品和教育目的)。我推了另一个以保留两个版本并保留跟踪改进的部件的可能性:
更新第一种方法 - 每列的顺序插入/更新(用法 游标,删除冗余临时表):
create procedure mysp_update (@table_name nvarchar(50), @column_name nvarchar(50), @column_value nvarchar(50))
as
begin
set nocount on;
declare @rows_count int
declare @query nvarchar(500)
declare @parm_definition nvarchar(100) = N'@column_value nvarchar(50)'
-- Update the row if it exists
set @query = N'update ' + quotename(@table_name) + N'set ' + quotename(@column_name) + N' = @column_value'
exec sp_executesql @query, @parm_definition, @column_value = @column_value
-- Insert the row if the update statement failed
if (@@rowcount = 0)
begin
set @query = N'insert into ' + quotename(@table_name) + N'(' + quotename(@column_name) + N') values (@column_value)'
exec sp_executesql @query, @parm_definition, @column_value = @column_value
end
end
go
create procedure mysp_xml_update (@table_name nvarchar(50), @data xml)
as
begin
set nocount on;
declare @name nvarchar(50), @value nvarchar(50)
-- Declare optimized cursor (fast_forward specifies forward_only, read_only cursor with performance optimizations enabled)
declare mycursor cursor fast_forward
for select
x.value(N'(name)[1]', N'nvarchar(50)'),
x.value(N'(value)[1]', N'nvarchar(50)')
from
@data.nodes(N'/properties/property') AS xtbl(x)
open mycursor
fetch next from mycursor into @name, @value
while @@fetch_status = 0
begin
-- Execute SP here (btw: SP cannot be executed from select statement)
exec mysp_update @table_name, @name, @value
-- Get the next row
fetch next from mycursor into @name, @value
end
close mycursor;
deallocate mycursor;
end
go
更新第二种方法 - 批量插入/更新:
create procedure mysp_xml_update (@table_name nvarchar(50), @data xml)
as
begin
set nocount on;
declare @name nvarchar(50), @value nvarchar(50)
-- Declare optimized cursor (fast_forward specifies forward_only, read_only cursor with performance optimizations enabled)
declare mycursor cursor fast_forward
for select
x.value(N'(name)[1]', N'nvarchar(50)'),
x.value(N'(value)[1]', N'nvarchar(50)')
from
@data.nodes(N'/properties/property') AS xtbl(x)
declare @insert_statement nvarchar(max) = N'insert into ' + quotename(@table_name) + N' ($columns$) values (''$values$)'
declare @update_statement nvarchar(max) = N'update ' + quotename(@table_name) + N' set $column$=''$value$'
open mycursor
fetch next from mycursor into @name, @value
while @@fetch_status = 0
begin
set @insert_statement = replace(@insert_statement, '$columns$', quotename(@name) + ',$columns$')
set @insert_statement = replace(@insert_statement, '$values$', @value + ''',''$values$')
set @update_statement = replace(@update_statement, '$column$', quotename(@name))
set @update_statement = replace(@update_statement, '$value$', @value + ''',$column$=''$value$')
fetch next from mycursor into @name, @value
end
close mycursor;
deallocate mycursor;
set @insert_statement = replace(@insert_statement, ',$columns$', '')
set @insert_statement = replace(@insert_statement, ',''$values$', '')
set @update_statement = replace(@update_statement, ',$column$=''$value$', '')
-- Update the row if it exists
exec sp_executesql @update_statement
-- Insert the row if the update statement failed
if (@@rowcount = 0)
begin
exec sp_executesql @insert_statement
end
end
go
最终,全新的第三种方法(动态批量合并与数据透视,无循环,无游标):
create procedure mysp_xml_update (@table_name nvarchar(50), @data xml)
as
begin
set nocount on;
declare @columns nvarchar(max), @scolumns nvarchar(max), @kvp nvarchar(max)='', @query nvarchar(max)
select @columns = coalesce(@columns + ',', '') + quotename(x.value(N'(name)[1]', N'nvarchar(50)')),
@scolumns = coalesce(@scolumns + ',', '') + 's.' + quotename(x.value(N'(name)[1]', N'nvarchar(50)')),
@kvp = @kvp + quotename(x.value(N'(name)[1]', N'nvarchar(50)')) + '=s.'
+ quotename(x.value(N'(name)[1]', N'nvarchar(50)')) + ','
from @data.nodes(N'/properties/property') as xtbl(x)
select @kvp = left(@kvp, len(@kvp)-1)
set @query = '
merge ' + quotename(@table_name) + ' t
using
(
select ' + @columns + ' from
(
select props.x.value(N''./name[1]'', N''nvarchar(50)'') as name,
props.x.value(N''./value[1]'', N''nvarchar(50)'') as value
from @data.nodes(N''/properties/property'') as props(x)
) properties
pivot
(
min(value) for name in (' + @columns + ')
) settings
) s (' + @columns + ')
on (1=1)
when matched then
update set ' + @kvp + '
when not matched then
insert (' + @columns + ')
values (' + @scolumns + ');'
exec sp_executesql @query, N'@data xml', @data = @data
end
go
用法如下:
exec mysp_xml_update N'mytable', N'<properties>
<property>
<name>DEFAULT_SETTING</name>
<value>NEW DEFAULT 3</value>
</property>
<property>
<name>SHOW_SETTING</name>
<value>NEW DEFAULT 2</value>
</property>
</properties>'