=?UTF-8?B?Qm9ydXQgQm9sxI1pbmE=?= <cayenn..mail.si> wrote:
> Hi to all,
> I read the thread with topic "Unique fields" and was wondering if the
> current best practice is the one suggested by Michael Gentry:
> * For your User DbEntity, mark emailAddress as the primary key
> * For your User ObjEntity, sync with the DbEntity and add emailAddress
> as an attribute
> * Generate your classes
> * In your database:
> * Create a unique index on emailAddress
> In your code (the registration page):
> * Create and register a new User object with your DataContext
> * Set their emailAddress/etc
> * commitChanges() and be ready to catch and sort out the exception
> So if I want to commit an object which has the same PK, I have to parse
> the CayenneRuntimeException (exception.getCause()) which would be
> "java.sql.SQLException: Duplicate entry....." and act accordingly?
If it's a primary key, I'd stick with the auto PK generation so it's handled
automatically for you.
If it's another unique field, I recommend setting the unique index on the
database, but still trying to detect it in your code beforehand.
Expression qualifier = ExpressionFactory.likeIgnoreCaseExp("emailAddress",
SelectQuery query = new SelectQuery(User.class, qualifier);
List results = aDataContext.performQuery(query);
if (0 != results.size()) // handle error
That lessens the likelihood that you'll have a constraint exception.
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