I need to update an XML document stored in a Microsoft SQL Server database, however the vendor of the product chose to store the XML in a TEXT column.
I've been able to extract the TEXT into an XML-type variable and perform the update I need on the xml within this variable, but when I try to UPDATE the column to push the change back to the database, I run into trouble.
Looking through the documentation it appears that it's not possible to simply CAST/CONVERT an XML type variable to insert it into a TEXT column, but I would think there is some way to extract the xml "string" from the XML-type variable and UPDATE the column using this value.
Any suggestions are appreciated, but I would like to keep the solution pure SQL that it can be run directly (no C# custom function, etc.); just to keep the impact on the database minimal.
(note: isn't it a bit absurd that you can't just CAST XML as TEXT? I'm just saying...)
Casting the XML as VARCHAR(MAX) works.
declare #xml xml
declare #tblTest table (
Id int,
XMLColumn text
)
insert into #tblTest
(Id, XMLColumn)
values
(1, '<MyTest><TestNode>A</TestNode></MyTest>')
set #xml = '<MyTest><TestNode>A</TestNode><TestNode>B</TestNode></MyTest>'
update #tblTest
set XMLColumn = cast(#xml as varchar(max))
where Id = 1
select Id, XMLColumn from #tblTest
Related
Let's say there is the following XML data and I want to add an attribute into salary like currency="INR":
<employee>
<salary amount="6000"/>
</employee>
If this data is stored in a column of type XML, then another attribute is being added easily just by using this code snippet:
UPDATE TABLENAME
SET COLUMNNAME.modify('insert attribute currency{"INR"} into (/employee/salary)[1]')
and if this data is stored in a column of type nvarchar(max), then the following query is not working even after casting the data as xml:
UPDATE TABLENAME
SET CAST(CAST(COLUMNNAME AS VARCHAR(MAX)) AS XML).modify('insert attribute currency{"INR"} into (/employee/salary)[1]')
So, help me to resolve second point as I have a column as nvarchar and I need to insert an attribute into saved xml data.
modify() Method works only with variable/column directly and can only used in the SET clause.
So, to solve this since you are storing your data as NVARCHAR, you have two choices:
Alter your table and add a new column with XML datatype, move the data to it from your column, and then UPDATE the data using modify()
Create/declare a table to store your data as XML and do the UPDATE.
Here is an example for what you provide:
CREATE TABLE T
(
Value NVARCHAR(MAX)
);
INSERT INTO T
SELECT N'<employee>
<salary amount="6000"/>
</employee>';
DECLARE #V XML;
SELECT #V = CAST(Value AS XML)
FROM T;
SET #V.modify('insert attribute currency{"INR"} into (/employee/salary)[1]');
UPDATE T
SET Value = CAST(#V AS NVARCHAR(MAX));
SELECT * FROM T;
Live demo
I am developing an sql server 2012 based application.
I am a newbie to SQl server. But the requirement is to use it.
One of the table I am using contains an XML Datatype column. However the data containing in that column may vary as per the xml element. The only thing in common is the root: For instance this is a sample data:
<Tags>
<key1>Value1</key1>
<key2>Value2</key2>
<key3>Value3</key3>
<key4>Value4</key4>
<key5>Value5</key5>
<key6>Value6</key6>
</Tags>
What I want to do is to query the whole table and fetch records that will match a specific key and a specific values sent by the user.
Please assist me.
Well it sounds like you need to use some variables to build an XQuery, yes? So, assuming you build a stored procedure or something which takes a pair of string arguments for key and value you could use the following example I've knocked up in SQL Fiddle so you can try it out.
DECLARE #key nvarchar(20)
DECLARE #value nvarchar(20)
SET #key = N'key5'
SET #value = N'Value5'
SELECT
TagValue = T1.xmlcol.value('(/Tags/*[local-name()=sql:variable("#key")])[1]', 'varchar(10)')
FROM
dbo.T1
WHERE
T1.xmlcol.exist('/Tags/*[local-name()=sql:variable("#key")][text() = "Value5"]') = 1
I am having an issue writing a trigger which is supposed to convert a row on a table to XML and writing it to a single column in another table. The Whenever a new row is inserted into this table (person.address) I want this trigger to send the row (converted to XML) to another table (audit.table) Here is my Trigger.
Create trigger [Person].[sPerson] ON [Person].[Address_s] for INSERT AS
begin
DECLARE #xml XML;
SET #xml =
(
SELECT [AddressID], [AddressLine1], [AddressLine2], [City], [StateProvinceID], [SpatialLocation.ToString()], [PostalCode], [rowguid], [ModifiedDate]
FROM INSERTED
FOR XML PATH('Inserted')
);
insert into AdventureWorks2012.HumanResources.Audit.Table(AuditXml) VALUES (#xml);
end
My error is
FOR XML does not support CLR types - cast CLR types explicitly into one of the supported types in FOR XML queries.
I have a column on the audit.table called AuditXml of type XML. It seems to think AuditXML is invalid. Thank you.
It is the column SpatialLocation in Person.Address that makes your for xml query to fail.
SpatialLocation is of type geography and that is a CLR type.
when we load xml into cursor then we specify column name and their datatype and size. instead of specifying manually how could i make that area dynamic. suppose my tsql as follows
Exec sp_xml_preparedocument #XMLFormat OUTPUT, #DetailXml
-- Create Cursor from XML Table
Declare CurDetailRecord
Cursor For
Select productid,unit,rate,qty,amount
From Openxml (#XMLFormat, '/NewDataSet/PurchaseOrderDetail', 2)
With
(
productid Varchar(10),
unit Varchar(50),
rate decimal(18,2),
qty decimal(18,3),
amount decimal(18,2)
)
here as a example
productid Varchar(10),
unit Varchar(50)
etc i am specifying and also specify their data tyoe & size.
so how could i construct this area dynamically and fetch the column name and data type & size dynamically.
please guide me thanks.
You can get column names(which are nodes inside PurchasePrderDetail node) like this:
declare #xml xml='<NewDataSet><PurchaseOrderDetail>
<productid>19125</productid>
</PurchaseOrderDetail></NewDataSet>'
SELECT b.value('local-name(.)','nvarchar(128)')ColumnName,
LEN(b.value('.','nvarchar(128)'))MaxLength
FROM #xml.nodes('/NewDataSet/PurchaseOrderDetail/*') a(b)
So you can generate dynamic SQL statement to create cursor with appropriate column names and length like varchar(MaxLength).
But you can not get datatypes from XML without knowing real column names because data in xml is just text and f.e. "5" can be int type and also just a text.
EDIT
If you know table name, you can built dynamic SQL statement using metadata from that table using this:
; With cols as(
SELECT COLUMN_NAME,
UPPER(DATA_type)
+
case when data_type like '%char' then
case when CHARACTER_MAXIMUM_LENGTH=-1 THEN ' (MAX)'
else ' ('+CAST(CHARACTER_MAXIMUM_LENGTH as nvarchar)+')'
END
ELSE ''
END ColConv
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME='PurchaseOrderDetail'),
XMLS as(
SELECT b.value('local-name(.)','nvarchar(128)')ColumnName,
b.value('.','nvarchar(128)')Value
FROM #xml.nodes('/NewDataSet/PurchaseOrderDetail/*') a(b)
)
SELECT XMLS.ColumnName,'CAST ('''+XMLS.Value+''' AS '+ ColConv+''')' FROM XMLS
JOIN cols ON XMLS.ColumnName=cols.COLUMN_NAME
As output you will have column name and value with appropriate CAST clause. Then you can build dynamic statement what you need.
Usually the information of data types and field names are describes in the XSD file (XML Schema Definition).
So you need to have a valid XSD file for each of your XML file then you can retrieve the fields name and data type.
Here a link to understand better the XSD
And here how to deal with XSD and XML step by step
Hope it helps you
My question is similar to this one: Choose a XML node in SQL Server based on max value of a child element
except that my column is NOT of type XML, it's of type nvarchar(max).
I want to extract the XML node values from a column that looks like this:
<Data>
<el1>1234</el1>
<el2>Something</el2>
</Data>
How can I extract the values '1234' and 'Something' ?
doing a convert and using the col.nodes is not working.
CONVERT(XML, table1.col1).value('(/Data/el1)[1]','int') as 'xcol1',
After that, I would like to do a compare value of el1 (1234) with another column, and update update el1 as is. Right now I'm trying to just rebuild the XML when passing the update:
ie
Update table set col1 ='<Data><el1>'+#col2+'</el1><el2>???</el2>
You've got to tell SQL Server the number of the node you're after, like:
(/Data/el1)[1]
^^^
Full example:
declare #t table (id int, col1 varchar(max))
insert #t values (1, '<Data><el1>1234</el1><el2>Something</el2></Data>')
select CAST(col1 as xml).value('(/Data/el1)[1]', 'int')
from #t
-->
1234
SQL Server provides a modify function to change XML columns. But I think you can only use it on columns with the xml type. Here's an example:
declare #q table (id int, col1 xml)
insert #q values (1, '<Data><el1>1234</el1><el2>Something</el2></Data>')
update #q
set col1.modify('replace value of (/Data/el1/text())[1] with "5678"')
select *
from #q
-->
<Data><el1>5678</el1><el2>Something</el2></Data>
At the end of the day, SQL Server's XML support makes simple things very hard. If you value maintainability, you're better off processing XML on the client side.