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From Borut BolĨina <borut.bolc...@gmail.com>
Subject Re: Context question
Date Fri, 15 Oct 2010 07:23:42 GMT
Hello Mathias,

context is similar to session in hibernate, but much better. The context is
where your persistent objects live in any of their possible state (
http://cayenne.apache.org/doc30/persistent-object-lifecycle.html).

You are trying to rollback database changes made in previous step. This is
not what context.rollback() does. See last paragraph at
http://cayenne.apache.org/doc30/dataobject-state-management.html.

When you do context.commit, you hit the database (or cache) if there are any
changes in the object graph you created or modified in the context you are
trying to commit.

What do you mean by: "How can I do some local changes to the dataset without
having to commit them to the database?"

Cheers,
Borut

2010/10/15 Mathias Clerc <tlarhices@gmail.com>

> Hello,
>
> I am making an evaluation of Cayenne and other frameworks.
>
> One of my test is the following :
>
> begin a set of operations
> make a select * on one table
> insert new element in that table
> make another select * on that table (see that new element along with
> the previous results)
> rollback
> make another select * on that table (see that it came back to it's
> original state)
>
>
> I am using the following code :
>        ObjectContext context1 = DataContext.createDataContext();
>        SelectQuery querySelectAll = new SelectQuery(Principal.class);
>        System.out.println("-test pre");
>        for (Object out : context1.performQuery(querySelectAll)) {
>            System.out.println(((Principal) out).getName());
>        }
>
>        Principal newPrincipal = context1.newObject(Principal.class);
>        newPrincipal.setName("toto");
>        context1.registerNewObject(newPrincipal); //Same with or
> without this line
>
>        SelectQuery querySelectAll2 = new SelectQuery(Principal.class);
>        System.out.println("-test post");
>        System.out.println("--c1");
>        for (Object out : context1.performQuery(querySelectAll2)) {
>            System.out.println(((Principal) out).getName());
>        }
>        System.out.println("--new context");
>        for (Object out :
> DataContext.createDataContext().performQuery(querySelectAll2)) {
>            System.out.println(((Principal) out).getName());
>        }
>
>        context1.rollbackChanges();
>        System.out.println("-test post rollback");
>        SelectQuery querySelectAll3 = new SelectQuery(Principal.class);
>        System.out.println("--c1");
>        for (Object out : context1.performQuery(querySelectAll3)) {
>            System.out.println(((Principal) out).getName());
>        }
>        System.out.println("--new context");
>        for (Object out :
> DataContext.createDataContext().performQuery(querySelectAll3)) {
>            System.out.println(((Principal) out).getName());
>        }
>
> And the output is :
> -test pre
> domain
> administrators
> admin
> -test post
> --c1
> domain
> administrators
> admin
> --new context
> domain
> administrators
> admin
> -test post rollback
> --c1
> domain
> administrators
> admin
> --new context
> domain
> administrators
> admin
>
> I think I have not understood completely what a context is.
> My question is in "test post" "c1" (created new element "toto", not
> commited, query done in the new element's context) shouldn't my new
> element appear ?
> If I do a commit on context1 then my element is visible, but it also
> hit the table.
>
> In case that behaviour is normal, how can I do some local changes to
> the dataset without having to commit them to the database ?
>
> Thank you,
>
> Tlarhices
>

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