Greets! Neat product. I'm having a newb issue which I'm hopeful someone can help
with. Here is the relevant layout: I have 2 tables (PARTY and CASE) and a third
lookup table which maps the many-to-many (PARTY_CASE_LINK) - since each party
can belong to 0 or more cases and each case can include 1 or more parties.
PARTY PARTY_CASE_LINK CASE
____________________ ____________________ ____________________
id party_id id
firm case_id foo
foo .. bar
I want to start my lookup by loading a party by criteria and being able to get
to all of the cases for that party. I have the relationships onships setup in
the modeler correctly (me thinks) -- since i am able to get a List<Party> and
from there I can use the relationships to get List<PartyCases> via
getPartyCases() and from there get List<Case> via getCases() -- works like a
charm!
I want to avoid an N+1 lookup, so I'm **attempting** to use addPrefetch to my
inial PARTY lookup. That's where it croaks.
I am also using FetchLimit and FetchOffset (not that I think it should matter,
but in full discolsure)
Expression qualifier = ExpressionFactory.matchExp(Party.FIRM_PROPERTY, firm);
SelectQuery selectQuery = new SelectQuery(Party.class, qualifier);
selectQuery.addOrdering(rs.getSort(), rs.isSortAscending());
selectQuery.setFetchLimit(rs.getPageSize());
selectQuery.setFetchOffset(rs.getStartIndex());
selectQuery.addPrefetch("partyCases");
paritesAttachedToFirm = (List<Party>) dataContext.performQuery(selectQuery);
09:46:46,558 DEBUG BeforeAfterMethodInterceptor:183 - Calling..efore method
'fillData' at LifecycleStage 'BindingAndValidation' on ActionBean
'JSONPartiesActionBean'
09:46:46,577 INFO QueryLogger:473 - --- will run 2 queries.
09:46:46,579 INFO QueryLogger:427 - --- transaction started.
09:46:46,620 INFO QueryLogger:357 - SELECT t0.middle_name, t0.last_name,
t0.sex, t0.firm_id, t0.id, t0.official_id_type, t0.party_type_id, t0.race,
t0.address_append_status_id, t0.dob, t0.invite_code, t0.dod, t0.first_name,
t0.official_id FROM PARTY t0 WHERE t0.firm_id = ? ORDER BY t0.last_name LIMIT 25
OFFSET 0 [bind: 1->firm_id:2] - prepared in 40 ms.
09:46:46,627 INFO QueryLogger:401 - === returned 25 rows. - took 48 ms.
09:46:46,631 INFO QueryLogger:357 - SELECT DISTINCT t0.case_id, t0.party_id
FROM PARTY_CASE_LINK t0 JOIN PARTY t1 ON (t0.party_id = t1.id) WHERE t1.firm_id
= ? [bind: 1->firm_id:2]
09:46:46,635 INFO QueryLogger:401 - === returned 110 rows. - took 8 ms.
09:46:46,636 INFO QueryLogger:434 - +++ transaction committed.
java.lang.ClassCastException: org.apache.cayenne.access.ToManyList cannot be
cast to org.apache.cayenne.Persistent at org.apache.cayenne.access.
ObjectTreeResolver$DisjointProcessor.startDisjointPrefetch
(ObjectTreeResolver.java:335)
at org.apache.cayenne.query.PrefetchTreeNode.traverse(PrefetchTreeNode.java:165)
What else can I tell you to help here:
In the modeler I have the relationship from PARTY to PARTY_CASE_LINK called
"partyCases" and it's "To Many" The reverse relationship is called "parties"
Thanks for your thoughts and advise.
Dan
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