Hi Sean, Can you: 1) Send me the DDL (SQL) for the tables in question? 2) Tell me about the cardinality AND directionality of all relations?
-Also please don't crosspost to [EMAIL PROTECTED] AND [EMAIL PROTECTED] and turn off HTML in your mail client if you can. Cheers, Aslak -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: 29. juli 2002 10:44 To: Aslak Hellesoy Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: RE: [Middlegen-user] Relation Table Relations HI, I've tried the many2many attribute, but for JBoss the tags produced aren't correct. :-( /** * Returns a collection of related uk.co.agora.hsbc.persistence.SurveyGroupLocal * * @return a collection of related uk.co.agora.hsbc.persistence.SurveyGroupLocal * * @ejb.interface-method view-type="local" * * @ejb.relation * name="SURVEY_GROUP-PERSON" * role-name="person-has-survey_group" * target-ejb="SurveyGroup" * target-role-name="survey_group-has-person" * target-multiple="yes" * * @debug M:N * * @jboss.relation * fk-constraint="true" * fk-column="PERSON_ID" * related-pk-field="personId" * * @jboss.relation * fk-constraint="true" * fk-column="SURVEY_ID" * related-pk-field="surveyId" * */ When I should have something more like: /** * Get the SurveyGroup for this Person. * * @return The SurveyGroupLocal for this Person. * * @ejb.interface-method view-type="local" * @ejb.relation * name="person-surveygroup" * role-name="one-person-belongsto-one-surveygroup" * target-ejb="SurveyGroup" * target-role-name="one-surveygroup-has-many-persons" * target-multiple="yes" * * @jboss.relation-mapping style="relation-table" * @jboss.relation-table table-name="SURVEY_GROUP_MEMBER" * @jboss.relation * related-pk-field="groupId" fk-column="GROUP_ID" * @jboss.target-relation * related-pk-field="personId" fk-column="PERSON_ID" * @jboss.target-relation * related-pk-field="surveyId" fk-column="SURVEY_ID" */ >One comment: You're saying that this kind of relation is "most commonly used >for bi-directional many to many relationships". Aren't they *always* >m:n? -Or did you mean "always used for many to many relationships, most >commonly bi-directional ones". I'm not trying to be picky here, just >wondering if you're referring to a concept I'm unfamiliar with. Relation tables aren't always used for M:N relations. Sometimes they are used as 1:1 (so you may need a way of specifying that). I also think that Dean Des Rosiers' ideas would be great. Regards, Sean Aslak Hellesoy <[EMAIL PROTECTED]> Sent by: [EMAIL PROTECTED] 28/07/2002 15:18 To: <[EMAIL PROTECTED]> cc: <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]> Subject: RE: [Middlegen-user] Relation Table Relations I understand what you mean now. Yes, Middlegen (CVS) does that if you set the many2many attribute of the <middlegen> task to true. (It defaults to false). Here is a sniplet of the docs under middlegen/docs/ant.html: "Set this to true if you want Middlegen to detect many-to-many relationships. If Middlegen stumbles upon three tables A, B and C where A and C have many Bs, it will consider A-C a possible many-to-many relationship where B is the join table." The CMR examples you refer to in XDoclet were actually produced by Middlegen ;-) One comment: You're saying that this kind of relation is "most commonly used for bi-directional many to many relationships". Aren't they *always* m:n? -Or did you mean "always used for many to many relationships, most commonly bi-directional ones". I'm not trying to be picky here, just wondering if you're referring to a concept I'm unfamiliar with. Cheers, Aslak -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of [EMAIL PROTECTED] Sent: 28. juli 2002 11:36 To: Aslak Hellesoy Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: RE: [Middlegen-user] Relation Table Relations Hi, There are 2 styles of relations that can be defined between Entity beans (how you do it is container specific). The first is via Foreign Keys, i.e. The table for one bean has a column(s) that represent the primary key(s) of the related bean and its table. The other is via a sperate Relation Table - one that has no coresponding entity bean. This relation table basically contains primary key information linking the two beans and is most commonly used for bi-directional many to many relationships. The XDoclet ejb cmr example illustrates all this very nicely. They are catered for in XDoclet 1.1 for Websphere, and now for JBoss 3 in XDoclet 1.2 (the CVS head version). Regards, Sean Aslak Hellesoy <[EMAIL PROTECTED]> Sent by: [EMAIL PROTECTED] 28/07/2002 04:33 To: <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]> cc: Subject: RE: [Middlegen-user] Relation Table Relations Hi Sean. I don't understand your question. Can you be more technical? Aslak -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of [EMAIL PROTECTED] Sent: 27. juli 2002 23:06 To: [EMAIL PROTECTED] Subject: [Middlegen-user] Relation Table Relations Hi, Can MiddleGen create Relation Table style relations for the entties? (and if so how?) (I'm using JBoss by the way) Thanks, Sean ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ middlegen-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/middlegen-user ------------------------------------------------------- This sf.net email is sponsored by: Dice - The leading online job board for high-tech professionals. 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