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
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>>
>> --
>> 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
>>
>>
>>
>>
>>
>>
>>
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