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From John Huss <johnth...@gmail.com>
Subject Re: SelectById vs SQLSelect cache behavior
Date Wed, 01 Aug 2018 18:14:27 GMT
If you want fresh data you shouldn't use .localCache() or you should pass a
cache strategy to refresh the cache.

You can also force objects to be refreshed on the next access or query by
using ObjectContext.invalidateObjects.

On Tue, Jul 31, 2018 at 6:35 PM kward@tybera.com <kward@tybera.com> wrote:

> I have a situation where multiple applications can make changes to the
> database, and I need to be able pull data from the database and not use
> cached data.
>
> We were running with cayenne 3.1M3 but I found documentation that
> indicated that SelectById may be better suited to do what I wanted than
> Cayenne.objectForPK which we were using - but I needed to update.  So I
> downloaded version 4.0.RC1 and changed this:
>         Employee  existingUserInfo = Cayenne.objectForPK(context,
> Employee.class, userInfo.getId());
> to this:
>         ObjectContext context = cayenneRuntime.getContext();
>         Employee  existingUserInfo = SelectById.query(Employee.class,
> userInfo.getId()).localCache().selectOne(context);
>
> This appears to have solved my problem.  However, I found that where I was
> calling SQLTemplate to get the Employee, that I am not getting the latest
> information because of the cache.  I switched these to use SQLSelect rather
> than SQLTemplate hoping that SQLSelect would act like SelectById, but it is
> not.
>
> Here is what I put in to try to test this:
>                         String sql = "SELECT * from Employee "
>                                         + " WHERE login_Id =
> #bind($loginId) "
>                                         + " and historical_Date is null ";
>
>                         ObjectContext context =
> cayenneRuntime.getContext();
>                         Employee emp = SQLSelect.query(Employee.class,
> sql).params("loginId", userName).localCache().selectOne(context);
>                         if (emp == null) return null;
>                         System.out.println("emp middleName=" +
> emp.getMiddleName());
>                         Employee emp2 = SelectById.query(Employee.class,
> emp.getObjectId()).localCache().selectOne(context);
>                         System.out.println("emp2 middleName=" +
> emp.getMiddleName());
>
> I access the Employee in my application, and then I change the middle name
> of the employee in the database.  The first call uses SQLSelect to get
> Employee emp based on their loginId.   Then I use SelectById to get the
> same Employee in emp2 based on the objectId for emp.  The calls follow the
> same pattern of specifying localCache and selectOne with the same context.
> However SQLSelect is not picking up the changed middle name, while
> SelectById does.
>
> What is the best approach to handling this?  I see that SQLSelect is a
> replacement for SQLTemplate with the new fluid approach, but I am hoping
> that I can switch to ObjectSelect and it will behave as SelectById.  I also
> wonder if I should be using ObjectContext context = runtime.newContext();
> rather than runtime.getContext();
>
> I am planning on updating to the new 4.1.M2 release.  I don't know if this
> gives me more/better options.
>
>
>
>
>
>

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