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.
