Has conditionals in table joiners been implemented?
jonwimp wrote: > > Hmm. > > Alright, answering my own questions again, in case anybody/I looks at the > mailing list archives in > future. > > Without conditionals (like "fieldA = 'SOME LITERAL') in table joiners, I > have to fall back on a > huge cross-product. > > While a huge and indiscriminately-built cross-product does work for my > query, the huge > cross-product is semantically wrong/incomplete. In other words, my query > is needed to make the > cross-product's definition complete. Obviously, any errors in the query > will completely change the > semantics for the cross-product. > > Hopefully RDBMSs optimize correctly when joiner conditionals are put into > the "WHERE" clause. I > would guess so, since such optimization is straightforward. If that isn't > the case, I'll have to > fall back on generating full lists (rather than using EntityListIterator). > > Jonathon > > Jonathon -- Improov wrote: >> David, >> >> Yeah, I would've thought that too, definitions should model only static >> structure. >> >> Given my first example, I would like to do a query like "find a Group >> that has all 3 kinds of members (LEADER, VICE, MEMBER)". >> >> Or even more complex: "find a Group where a/the leader's name is like >> Blah, a/the vice's name is like Bleh, and a/the member's name is like >> Bluh". >> >> I've having difficulty putting that into a view-entity and generating a >> resultant ListIterator with GenericDelegator. >> >> Help? Thanks! >> >> Jonathon >> >> David E Jones wrote: >>> >>> In general entity and view entity definitions are meant to model >>> structure, not query constraints. Just add your desired constraints to >>> the EntityCondition passed into the findByCondition call (or Map for >>> findByAnd or whatever). >>> >>> -David >>> >>> >>> Jonathon -- Improov wrote: >>>> Hi Rodrigo, >>>> >>>> Are you absolutely sure that works? >>>> >>>> First, your suggestion throws an exception. Note that there is no >>>> such field as Member.leaderId. >>>> >>>> Second, do take a look at SqlJdbcUtil.java method makeFromClause(). >>>> That's where you'll see the joins being made. You'll also see that >>>> this isn't possible: >>>> >>>> "... <table1> JOIN <table2> ON (<table1>.partyId = <table2>.partyId >>>> AND <table2>.roleId = 'LEADER') ..." >>>> >>>> What is possible is only: >>>> >>>> "... <table1> JOIN <table2> ON (<table1>.partyId = <table2>.partyId) >>>> ..." >>>> >>>> So, to answer my own question, the OFBiz Entity framework doesn't >>>> seem to handle what I requested for. >>>> >>>> Perhaps I'm not understanding your suggestion? Would you mind >>>> indicating whether you are sure the suggestion works or whether it's >>>> a mere guess? Thanks. >>>> >>>> If you are sure it works, I'll spend more time trying your >>>> suggestion. But from first impressions, you may have missed something >>>> because it throws an error. >>>> >>>> Jonathon >>>> >>>> Rodrigo Souza wrote: >>>>> Add to your code: >>>>> >>>>> <key-map field-name="roleId" rel-field-name="leaderId"/> >>>>> >>>>> i.e >>>>> >>>>>> <view-link entity-alias="GP" rel-entity-alias="LD" >>>>>> rel-optional="true"> >>>>>> <!-- Where LD.roleId is "LEADER" --> >>>>> <key-map field-name=roleId" rel-field-name="leaderId"/> >>>>>> </view-link> >>>>> >>>>> >>>>> 2007/8/6, Jonathon -- Improov <j...@improov.com>: >>>>>> In view-entity(s), is it possible to have conditionals in <relation>? >>>>>> >>>>>> For eg, an entity Group can have 3 types of members: "LEADER", >>>>>> "VICE" and "MEMBER". >>>>>> >>>>>> I've included my thoughts in the crude example below (please ignore >>>>>> syntax errors). >>>>>> >>>>>> <entity entity-name="Group"> >>>>>> <field name="groupId"/> >>>>>> </entity> >>>>>> >>>>>> <entity entity-name="Member"> >>>>>> <field name="memberId"/> >>>>>> <field name="groupId"/> >>>>>> <field name="roleId"/> >>>>>> <relation rel-entity-name="Group"> >>>>>> <key-map field-name="groupId"/> >>>>>> </relation> >>>>>> </entity> >>>>>> >>>>>> <view-entity entity-name="GroupAndMember"> >>>>>> <member-entity entity-alias="GP" entity-name="Group"/> >>>>>> <member-entity entity-alias="LD" entity-name="Member"/> >>>>>> <member-entity entity-alias="VC" entity-name="Member"/> >>>>>> <member-entity entity-alias="MB" entity-name="Member"/> >>>>>> <alias-all entity-alias="GP"/> >>>>>> <alias entity-alias="LD" name="leaderId" field-name="memberId"/> >>>>>> <alias entity-alias="VC" name="viceId" field-name="memberId"/> >>>>>> <alias entity-alias="MB" name="memberId" field-name="memberId"/> >>>>>> <view-link entity-alias="GP" rel-entity-alias="LD" >>>>>> rel-optional="true"> >>>>>> <!-- Where LD.roleId is "LEADER" --> >>>>>> </view-link> >>>>>> <view-link entity-alias="GP" rel-entity-alias="VC" >>>>>> rel-optional="true"> >>>>>> <!-- Where VC.roleId is "VICE" --> >>>>>> </view-link> >>>>>> <view-link entity-alias="GP" rel-entity-alias="MB" >>>>>> rel-optional="true"> >>>>>> <!-- Where MB.roleId is "MEMBER" --> >>>>>> </view-link> >>>>>> </entity> >>>>>> >>>>>> I know that I can simply use different entities for leader, vice >>>>>> and member (eg Leader, Vice and >>>>>> Member). But that would be a little awkward, since all the 3 >>>>>> entities will have exactly the same >>>>>> fields (just different roleIds). >>>>>> >>>>>> Is the above possible in OFBiz's Entity framework? >>>>>> >>>>>> Jonathon >>>>>> >>>>> >>>>> >>>> >>> >>> >> >> > > > -- View this message in context: http://www.nabble.com/Conditions-in-table-joiners-tp12018323p24717097.html Sent from the OFBiz - User mailing list archive at Nabble.com.
