do you insert the Enterprise Object in the Editing Context immediately after 
creation or when submitting form ?


On 07/apr/2011, at 12.39, Pascal Robert wrote:

> 
> Le 2011-04-06 à 23:48, Chuck Hill a écrit :
> 
>> That is going to leave you with a race condition.  The only certain way to 
>> prevent the creation of duplicates is to put an unique constraint on the 
>> database.  Then you have to catch the database exception 
>> (EOGeneralAdaptorException) in your code and handle appropriately.  The ugly 
>> part is that the exception message returned is different for each database 
>> which makes doing this in a database agnostic way slightly challenging.
> 
> Example for H2:
> 
>   try {
>     editingContext().saveChanges();
>   } catch (EOGeneralAdaptorException ex) {
>     EOAdaptorOperation operation = 
> (EOAdaptorOperation)((NSMutableArray)ex.userInfo().valueForKey("EOAdaptorOperationsKey")).objectAtIndex(0);
>     if (operation.exception().getMessage().contains("Unique index or primary 
> key violation")) {
>       throw new SomeException();
>     }
> 
>> Chuck
>> 
>> On Apr 6, 2011, at 8:21 PM, Paul D Yu wrote:
>> 
>>> Based on the column/attribute in your DB/EOModel that would make your 
>>> consider the record/EO to be duplicate of another, you should implement a 
>>> method that would check for those values in the existing set.
>>> 
>>> I don't think there is a one line solution to what you are seeking.
>>> 
>>> Paul
>>> On Apr 6, 2011, at 10:52 PM, Mr Tonnew wrote:
>>> 
>>>> Hi,
>>>> 
>>>> How do I avoid committing duplicate entries in the DB? I have a form
>>>> from where I take entries. Is there a single line of code that can
>>>> accomplish this?
>>>> 
>>>> MR
>>>> _______________________________________________
>>>> Do not post admin requests to the list. They will be ignored.
>>>> Webobjects-dev mailing list      (Webobjects-dev@lists.apple.com)
>>>> Help/Unsubscribe/Update your Subscription:
>>>> http://lists.apple.com/mailman/options/webobjects-dev/pyu%40mac.com
>>>> 
>>>> This email sent to p...@mac.com
>>> 
>>> _______________________________________________
>>> Do not post admin requests to the list. They will be ignored.
>>> Webobjects-dev mailing list      (Webobjects-dev@lists.apple.com)
>>> Help/Unsubscribe/Update your Subscription:
>>> http://lists.apple.com/mailman/options/webobjects-dev/chill%40global-village.net
>>> 
>>> This email sent to ch...@global-village.net
>> 
>> -- 
>> Chuck Hill             Senior Consultant / VP Development
>> 
>> Practical WebObjects - for developers who want to increase their overall 
>> knowledge of WebObjects or who are trying to solve specific problems.    
>> http://www.global-village.net/products/practical_webobjects
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> _______________________________________________
>> Do not post admin requests to the list. They will be ignored.
>> Webobjects-dev mailing list      (Webobjects-dev@lists.apple.com)
>> Help/Unsubscribe/Update your Subscription:
>> http://lists.apple.com/mailman/options/webobjects-dev/probert%40macti.ca
>> 
>> This email sent to prob...@macti.ca
> 
> _______________________________________________
> Do not post admin requests to the list. They will be ignored.
> Webobjects-dev mailing list      (Webobjects-dev@lists.apple.com)
> Help/Unsubscribe/Update your Subscription:
> http://lists.apple.com/mailman/options/webobjects-dev/amedeomailing%40insigno.it
> 
> This email sent to amedeomail...@insigno.it
> 

 _______________________________________________
Do not post admin requests to the list. They will be ignored.
Webobjects-dev mailing list      (Webobjects-dev@lists.apple.com)
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com

This email sent to arch...@mail-archive.com

Reply via email to