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From "Philippe Peuret" <philippe.peu...@neoxia.com>
Subject RE : iBatis.Net - Optimistic concurrency control
Date Thu, 19 Apr 2007 12:20:40 GMT
I agree with your two solutions, but each time, there is two diferrent parameter in the SQL
query : the first parameter is the Object to update (with all its data) and the second parameter
is the timestamp or a second object which contains data of the original object. So, how do
you do to pass two parameters to the SQL query ?
 
In the examples below, you can see only one parameter for the current object "Employee" :
 
<update id="UpdateEmployee" parameterClass="Employee">
UPDATE dbo.Employee 
SET FirstName = #_firstNam#,
       LastName = #_lastName#,
       SSN = #_ssn#
WHERE EmployeId = #_employeeId#
AND [Timestamp] = #_timestamp#
</update> 
 
or
 
<update id="UpdateEmployee" parameterClass="Employee">

UPDATE dbo.Employee

SET FirstName = #_firstName#

            , LastName = #_lastName#

            , SSN = #_ssn#

WHERE FirstName = #OriginalObject._firstName#

            AND LastName = #OriginalObject._lastName#

            AND SSN = #OriginalObject._ssn#

</update>

 
________________________________

De: Henrik Uffe Jensen [mailto:huj@corewit.com]
Date: mer. 18-avr.-07 20:43
À: user-cs@ibatis.apache.org
Objet : Re: iBatis.Net - Optimistic concurrency control


Another solution :
 
Make timestamp column (SQL Server but probably similary data types in other databases). This
column is automatically updated by
sql server each time the row is changed, so you know that if the timestamp column has changed
since you pulled out the data then 
there is a concurrency violation. So in your updates / deletes you add [Timestamp] = #_timeStamp#
to your where clause, for example
 
UPDATE dbo.Employee 
SET FirstName = #_firstNam#,
       LastName = #_lastName#,
       SSN = #_ssn#
WHERE EmployeId = #_employeeId#
AND [Timestamp] = #_timestamp#
   
You can then use the rows affected returned by the Delete/Update methods on the SqlMapper,
and if it's 0 then at there is a concurrency
violation and you can throw an exception or whatever you do.
 
regards
 
Henrik Uffe Jensen

	----- Original Message ----- 
	From: Nguyen, Tom <mailto:Tom.Nguyen@rels.info>  
	To: user-cs@ibatis.apache.org 
	Sent: Wednesday, April 18, 2007 8:04 PM
	Subject: RE: iBatis.Net - Optimistic concurrency control


	Unless I'm behind on my knowledge, I don't believe that iBatis.Net has automatic optimistic
concurrency implementation.  You will have to implement this yourself.

	 

	This is the pseudo of how I implemented mine:

	BusinessBase<T> : IClonable

	-Clone()

	-OriginalObject AS T

	 

	Employee : BusinessBase<Employee>

	-SSN

	-FirstName

	-LastName

	 

	1.	Retrieve Employee 
	2.	Clone Employee and store in OriginalObject 
	3.	Employee is parameter class of Update Ibatis Mapping 

	 

	UPDATE dbo.Employee

	SET FirstName = #_firstName#

	            , LastName = #_lastName#

	            , SSN = #_ssn#

	WHERE FirstName = #OriginalObject._firstName#

	            AND LastName = #OriginalObject._lastName#

	            AND SSN = #OriginalObject._ssn#

	 

	 

	Unless you have build some kind of framework to do this, it is a lot of manual, repetitive
work.  Only do it when you really need to.

	 

	Regards,

	
	Tom Nguyen 
	Sr. Developer
	tom.nguyen@rels.info <mailto:tom.nguyen@rels.info> 
	
	

	
________________________________


	From: Philippe Peuret [mailto:philippe.peuret@neoxia.com] 
	Sent: Wednesday, April 18, 2007 7:20 AM
	To: user-cs@ibatis.apache.org
	Subject: TR: iBatis.Net - Optimistic concurrency control

	 

	Hello,

	 

	How to use the optimistic concurrency control when we update the database with iBatis.Net
?

	Because, when we use the <insert> or <update> elements, we can only pass one
parameter : the object to insert or to update. But there is no other parameter to pass the
data to the optimistic concurrency control.

	 

	Thank you for your help.

	
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