Re: [eclipselink-users] Using several collection mapping of the same typ

[Pierre-Yves Saumont <pys@xxxxxxxx>]

Hello Chris,

My use case is not to null the whole collection, but only to remove
elements. This could result in removing all elements corresponding to one
property, but it should not cause any problem. By the way, once the tables
are modified to include a default value (an empty string), it seems to work
fine.

As our code is automatically generated, we need to minimize configuration.
Setting a join table explicitly is a problem because the code generator has
to figure if other properties of the same type exist in the class, or
alternately, it has to specify a join table for all properties.

So my question is: Is the lack of a default value in the generated tables a
bug? Or is it something choosen to discourage the use of multicolumn joint
tables while conforming to the spec?

Best regards,

Pierre-Yves



Christopher Delahunt wrote:
> 
> Hello Pierre-Yves,
> 
> The JPA specification mandated that relation table names default to 
> CLASSA_CLASSB, causing problems when using defaults and having more than 
> one collection mapping requiring a relation table (M:M or 
> uni-directional 1:M mappings).
> 
> I don't remember off hand how EclipseLink will remove an entire 
> collection, but if you null out one collection and not the other, you 
> might get into problems where the provider might use Delete from 
> CLIENT_ORDER where (CLIENT_UNIQUEID = x). 
> 
> Best Regards,
> Chris
> 
> Pierre-Yves SAUMONT wrote:
>> Hello Chris,
>>
>> Thanks for the info. It's difficult to understand why Eclipselink does 
>> this (create a multicolumn join table) if it can't work!
>> While testing it (after modifying the table to have a default value of 
>> ""), the result is that deleting works fine except for the last item 
>> in the table (whatever the order of creation).
>>
>> Beside using separate tables (which I am going to try asap), could you 
>> please elaborate on the reason why removing is causing problems ?
>>
>> Thanks,
>>
>> Pierre-Yves
>>
>>
>> christopher delahunt wrote:
>>> Hello,
>>>
>>> They should not be using the same relation table.  You need to define 
>>> atleast one of the OntToMany mappings to use different table using 
>>> the JoinTable annotation or you will get into problems when it tries 
>>> to remove from the table as well.
>>>
>>> Best Regards,
>>> Chris
>>>
>>> Pierre-Yves SAUMONT wrote:
>>>> Hi,
>>>>
>>>> I could not find information about the following case: An entity as 
>>>> several properties that are collection of another same entity.
>>>>
>>>> For example, a Client entity has a collection of Order called 
>>>> executedOrderList and a second called pendingOrderList.
>>>>
>>>> This is declared in Client as :
>>>>
>>>> @OneToMany(cascade = CascadeType.ALL)
>>>> List<Order> executedOrderList;
>>>>
>>>> @OneToMany(cascade = CascadeType.ALL)
>>>> Lsit<Order> pendingOrderList;
>>>>
>>>> This results is an table called CLIENT_ORDER with three columns:
>>>>
>>>> CLIENT_UNIQUEID, EXECUTEDORDERLIST_UNIQUEID, PENDINGORDERLIST_UNIQUEID
>>>>
>>>> with a composite primary key:
>>>>
>>>> PRIMARY KEY CLIENT_UNIQUEID, EXECUTEDORDERLIST_UNIQUEID, 
>>>> PENDINGORDERLIST_UNIQUEID
>>>>
>>>> so far, so good.
>>>>
>>>> The problem is that all three columns in that table must be non null 
>>>> and have no default value which result in an error as soon as one 
>>>> entry is added since it automatically have one of the two last 
>>>> column null.
>>>>
>>>> I can workaround this by editing the create.sql generated file and 
>>>> either adding DEFULT "" or removing NOT NULL.
>>>>
>>>> My question is how can I make eclipselink generate this correctly, 
>>>> so that I do not need to edit the generated SQL manually ?
>>>>
>>>> Pierre-Yves
>>>> _______________________________________________
>>>> eclipselink-users mailing list
>>>> eclipselink-users@xxxxxxxxxxx
>>>> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
>>> _______________________________________________
>>> eclipselink-users mailing list
>>> eclipselink-users@xxxxxxxxxxx
>>> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
>>
>> _______________________________________________
>> eclipselink-users mailing list
>> eclipselink-users@xxxxxxxxxxx
>> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
> _______________________________________________
> eclipselink-users mailing list
> eclipselink-users@xxxxxxxxxxx
> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
> 
> 

-- 
View this message in context: http://www.nabble.com/Using-several-collection-mapping-of-the-same-type-tp24304188p24325963.html
Sent from the EclipseLink - Users mailing list archive at Nabble.com.