[ http://jira.andromda.org/browse/EJB-35?page=comments#action_12942 ]
Vance Karimi commented on EJB-35: --------------------------------- Perhaps continue to use @andromda.ejb.query or OCL for now. I would like to wait until we have defined entity metadata in the ORM mapping file and see if it's possible to manually over-write the NameQuery in the entity implementation. Failing this, we could change things slightly to only define OCL queries as NamedQueries. Queries defined by tagged value or left undefined are set directly in the finder method of the DAO (without a NamedQuery). Another alternative: once the ORM mapping file is in place for entities, we could define named queries there and introduce a merge point for every entity such that one can set those 'undefined' queries manually in the merge file. > Finder methods, named queries and relations > ------------------------------------------- > > Key: EJB-35 > URL: http://jira.andromda.org/browse/EJB-35 > Project: EJB Cartridge > Type: Improvement > Reporter: Sverker Abrahamsson > Assignee: Vance Karimi > Priority: Trivial > Attachments: andromda-all.patch, andromda-plugins.patch > > Most of my queries involve related classes. For example, I have an entity > Subscription with a 0-n relation to entity User and a n-1 relation to entity > Channel. I want a finder method which returns all channels a given user is > subscribed to, without having to load neither the User nor the Subscription > entities (this is a quite trivial example, there are more complicated cases > where the difference acctually affects performance). > So I create a finder method in Channel called findSubscribedChannels(String > msisdn) where msisdn is primary key of User entity. This finder method should > return a collection of channels the given user is subscribed to. > The generated query is of course not correct but I thought it sholdn't be a > problem as I could override it in the DaoImpl class, but the problem is that > since it's created as a named query then JBoss verifies it when the > application is deployed and fails since Channel doesn't have any field named > msisdn. > As the doc indicated that there are no possibility to override the generated > query except by creating a OCL query, I started to ponder how to solve this > issue (I later found that @andromda.ejb.query tagged value does work > countrary to what the doc says). I thought that if I instead specified the > signature as findSubscribedChannels(String subscriptions.user.msisdn) (where > subscriptions and user are the respective relation names) then the query > generator could detect that this finder argument refers to a field in a > related entity. It acctually worked out very conveniently. For this finder > method a query like this is generated: > select channel from Channel as channel inner join channel.subscriptions > as subscription where > subscription.user.msisdn = :subscriptionsUserMsisdn > Hence as long as just a simple query is neccesary then nothing else than > specifying the finder parameters results in a working query even when the > query involves several related enties. > To make it work I had to do a patch also for the main andromda project as the > signature of a finder method is created there but unless a operation > parameter name is allowed to have dot's in some context (I can't think of > any) it shouldn't affect anything negatively. > Now that I found out that I can override the named query with > @andromda.ejb.query maybe this patch isn't that neccesary but I still find it > convenient as it makes it visible directly in the model which attributes are > involved in the search. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://jira.andromda.org/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
