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From Peter Mills <developm...@peter.mills.to>
Subject Re: iBatis.Net - Optimistic concurrency control
Date Thu, 19 Apr 2007 17:53:10 GMT
Actually, raising an error from t-sql is probably unnecessary, unless 
you're doing multiple updates from inside a stored procedure, and even 
then, there may be a better way.  IBatis' update method returns the 
number of effected rows, even from a stored procedure, on MS SQL 
Server.  For compatibility, does anyone know if the update method can 
return the number of effected rows from Oracle or DB2 stored procedures?

Cheers,

Peter

Peter Mills wrote:

> What ways are everyone using to alert the application, when a 
> concurrency check fails?  Are you checking the number of changed rows, 
> after the update statement, and raising an error?
> Cheers,
>
> Peter
>
> Henrik Uffe Jensen wrote:
>
>> Timestamp is a property on the object, so only one parameter (the 
>> object) is passed
>>  
>> Employee.FirstName
>> Employee.LastName
>> Employee.TimeStamp
>>  
>> With Toms solution then there is a property called OriginalObject on 
>> the object to update as far
>> as I understand the solution, so again only one parameter
>>  
>> Employee.FirstName
>> Employee.LastName
>> Employee.OriginalObject.FirsName
>> Employee.OriginalObject.LastName
>>  
>> regards
>>  
>> Henrik Uffe Jensen
>> Corewit
>>
>>     ----- Original Message -----
>>     *From:* Philippe Peuret <mailto:philippe.peuret@neoxia.com>
>>     *To:* user-cs@ibatis.apache.org <mailto:user-cs@ibatis.apache.org>
>>     *Sent:* Thursday, April 19, 2007 2:20 PM
>>     *Subject:* RE : iBatis.Net - Optimistic concurrency control
>>
>>     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 <mailto: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 <mailto: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>
>>     <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 <mailto: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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>>
>>
>>
>>
>>
>>
>
>
>



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