5 Replies Latest reply on Jun 20, 2003 7:53 AM by null null

    CMP-Relation (m-n)

    helgi Newbie

      Hi there,

      i'm just writing an example app for myself. I want to have costumers and books. A customer should be able to sign many books.
      A book is signable by many customers.
      The primary key for my customer is his login (a String)
      The primary key for the book is an ISBN-number (Integer)

      My jbosscmp-jdbc looks for that part like that:

      <ejb-relation>
      <ejb-relation-name>Book-Customer</ejb-relation-name>
      <relation-table-mapping>
      <table-name>BOOK_SIGNER</table-name>
      <create-table>true</create-table>
      <remove-table>true</remove-table>
      </relation-table-mapping>

      <ejb-relationship-role>
      <ejb-relationship-role-name>Book-AllSigners</ejb-relationship-role-name>
      <key-fields>
      <key-field>
      <field-name>login</field-name>
      <column-name>customer_login</column-name>
      </key-field>
      </key-fields>

      </ejb-relationship-role>
      <ejb-relationship-role>
      <ejb-relationship-role-name>Customer-SignedBooks</ejb-relationship-role-name>
      <key-fields>
      <key-field>
      <field-name>isbn</field-name>
      <column-name>book_isbn</column-name>
      </key-field>
      </key-fields>

      </ejb-relationship-role>
      </ejb-relation>

      When I try to deploy my App I'm getting the error "CMP field for key not found: field name=login"

      But there ist a field login.
      I want to use Hypersonic SQL with Jboss 3.0.6
      What's going wrong here?
      Thanks for your advices.

      Greets,

      helgi

        • 1. Re: CMP-Relation (m-n)
          null null Newbie

          The syntax is correct, it depends what you have specified
          in the
          ejb-jar.xml
          or/and
          jbossjdbc-cmp.xml (At the table definition)

          the field-name for many-many relation has to be
          same as primary key field-name from entity "customers"

          (the CMP field "login" must be specified in "customers" entity bean as primary key)

          + don't forget to preserve same order of relation definition in ejb-jar.xml

          hope it helps

          send ejb-jar.xml definition for entity customers and relation

          • 2. Re: CMP-Relation (m-n)
            helgi Newbie

            Thanks for your answer.

            My ejb-jar.xml for customer looks like that:


            <![CDATA[]]>

            <ejb-name>Customer</ejb-name>

            CustomerHome
            Customer
            <local-home>CustomerLocalHome</local-home>
            CustomerLocal
            <ejb-class>CustomerCMP</ejb-class>
            <persistence-type>Container</persistence-type>
            <prim-key-class>java.lang.String</prim-key-class>
            false
            <cmp-version>2.x</cmp-version>
            <abstract-schema-name>Customer</abstract-schema-name>
            <cmp-field >
            <![CDATA[]]>
            <field-name>password</field-name>
            </cmp-field>
            <cmp-field >
            <![CDATA[]]>
            <field-name>login</field-name>
            </cmp-field>
            <cmp-field >
            <![CDATA[]]>
            <field-name>prename</field-name>
            </cmp-field>
            <cmp-field >
            <![CDATA[]]>
            <field-name>name</field-name>
            </cmp-field>
            <cmp-field >
            <![CDATA[]]>
            <field-name>boorowdbooks</field-name>
            </cmp-field>
            <cmp-field >
            <![CDATA[]]>
            <field-name>signedBooks</field-name>
            </cmp-field>
            <primkey-field>login</primkey-field>



            For the relations I have the following:


            <ejb-relation >
            <ejb-relation-name>Book-Customer</ejb-relation-name>

            <ejb-relationship-role >
            <ejb-relationship-role-name>Book-AllSigners</ejb-relationship-role-name>
            Many
            <relationship-role-source >
            <ejb-name>Book</ejb-name>
            </relationship-role-source>
            <cmr-field >
            <cmr-field-name>signers</cmr-field-name>
            <cmr-field-type>java.util.Set</cmr-field-type>
            </cmr-field>
            </ejb-relationship-role>

            <ejb-relationship-role >
            <ejb-relationship-role-name>Customer-SignedBooks</ejb-relationship-role-name>
            Many
            <relationship-role-source >
            <ejb-name>Kunde</ejb-name>
            </relationship-role-source>
            <cmr-field >
            <cmr-field-name>signedBooks</cmr-field-name>
            <cmr-field-type>java.util.Set</cmr-field-type>
            </cmr-field>
            </ejb-relationship-role>

            </ejb-relation>

            Any Ideas?

            • 3. Re: CMP-Relation (m-n)
              null null Newbie

              The first mistake is
              <ejb-name>Book</ejb-name>

              it should be
              <ejb-name>Customer</ejb-name>

              (since you are using "login" field of Customers in jbossjdbc-cmp.xml - the relation must be in same order)


              I don't know what the Kunde stands for
              (did I miss the point?)

              also replce
              <ejb-name>Kunde</ejb-name>

              with
              <ejb-name>Books</ejb-name>

              (only if you are using "isbn" field of Books in jbossjdbc-cmp.xml, if not leave it as it is)



              Hope it helps


              lp

              Nikola

              • 4. Re: CMP-Relation (m-n)
                helgi Newbie

                Hi Nicolai,

                sorry, Kunde is the german word for customer. I wrote the app with german words an translated the whole thing for the postings and missed that one.

                Is it correct that the order of the <ejb-relationship-role>s in jbosscmp-jdbc has to be the same as the order in ejb-jar?

                When I switch the <ejb-relationship-role >
                -entries in ejb-jar.xml (now Customer comes first and afterwards the book) I get the error that the field for key "isbn" could not be found.

                The next thing is that all my deployment-descriptors are generated by XDoclet. I hope that tool generates the files in correct order.
                I have no idea whats the cause. I hope you do.

                Thank you very much for your help!

                helgi

                • 5. Re: CMP-Relation (m-n)
                  null null Newbie

                  can you send me the generated XML files

                  (ejb-jar.xml, jbossjdbc-cmp.xml)

                  nikola@rs-pi.com

                  You were right about the orders of the <ejb-relationship-role>s

                  I think that XDoclet should do it right, but I write them by
                  hand. (Don't know much about XDoclet)

                  p.s. Leave it in german

                  lp

                  Nikola


                  this is my example

                  two entity beans cmpUsers and cmpFsItems
                  in many to many relation.


                  <display-name>File system items CMP Bean</display-name>
                  <ejb-name>cmpFsItems</ejb-name>

                  <local-home>com.rspi.pms.cmp.FsItemsHome</local-home>
                  com.rspi.pms.cmp.FsItems
                  <ejb-class>com.rspi.pms.cmp.FsItemsBean</ejb-class>

                  <persistence-type>Container</persistence-type>
                  <prim-key-class>java.lang.Long</prim-key-class>
                  False
                  <cmp-version>2.x</cmp-version>
                  <abstract-schema-name>fs_items</abstract-schema-name>

                  <cmp-field><field-name>fsItemId</field-name></cmp-field>
                  <cmp-field><field-name>name</field-name></cmp-field>
                  <!--this is optional if you need a reference to fsItems in EJBQL query-->
                  <cmr-field><field-name>favouritesUsers</field-name></cmr-field>
                  <primkey-field>fsItemId</primkey-field>




                  <display-name>Users Entity CMP Bean</display-name>
                  <ejb-name>cmpUsers</ejb-name>

                  <local-home>com.rspi.pms.cmp.UsersHome</local-home>
                  com.rspi.pms.cmp.Users
                  <ejb-class>com.rspi.pms.cmp.UsersBean</ejb-class>

                  <persistence-type>Container</persistence-type>
                  <prim-key-class>java.lang.Long</prim-key-class>
                  False
                  <cmp-version>2.x</cmp-version>
                  <abstract-schema-name>users</abstract-schema-name>

                  <cmp-field><field-name>userId</field-name></cmp-field>
                  <cmp-field><field-name>userName</field-name></cmp-field>

                  <!--this is optional if you need a reference to fsItems in EJBQL query-->
                  <cmr-field><field-name>userFavourites</field-name></cmr-field>

                  <primkey-field>userId</primkey-field>





                  <!-- (users - fs-items) = favourites many-many -->
                  <ejb-relation>
                  <ejb-relation-name>user_favourites</ejb-relation-name>
                  <ejb-relationship-role>
                  <ejb-relationship-role-name>user-has-favourites</ejb-relationship-role-name>

                  Many

                  <relationship-role-source>
                  <ejb-name>cmpUsers</ejb-name>
                  </relationship-role-source>

                  <cmr-field>
                  <cmr-field-name>userFavourites</cmr-field-name>
                  <cmr-field-type>java.util.Collection</cmr-field-type>
                  </cmr-field>
                  </ejb-relationship-role>
                  <ejb-relationship-role>
                  <ejb-relationship-role-name>favourites-has-users</ejb-relationship-role-name>

                  Many

                  <relationship-role-source>
                  <ejb-name>cmpFsItems</ejb-name>
                  </relationship-role-source>

                  <cmr-field>
                  <cmr-field-name>favouritesUsers</cmr-field-name>
                  <cmr-field-type>java.util.Collection</cmr-field-type>
                  </cmr-field>
                  </ejb-relationship-role>
                  </ejb-relation>





                  ---------------------------------------jbossjdbc-cmp.xml


                  <!-- (users - fs-items) = favourites many-many -->
                  <ejb-relation>
                  <ejb-relation-name>user_favourites</ejb-relation-name>
                  <relation-table-mapping>
                  <table-name>fs_items_favourites</table-name>
                  </relation-table-mapping>
                  <ejb-relationship-role>
                  <ejb-relationship-role-name>user-has-favourites</ejb-relationship-role-name>
                  <key-fields>
                  <key-field>
                  <field-name>userId</field-name>
                  <column-name>user_id</column-name>
                  </key-field>
                  </key-fields>
                  <read-ahead>on-load</read-ahead>
                  </ejb-relationship-role>
                  <ejb-relationship-role>
                  <ejb-relationship-role-name>favourites-has-users</ejb-relationship-role-name>
                  <key-fields>
                  <key-field>
                  <field-name>fsItemId</field-name>
                  <column-name>fs_item_id</column-name>
                  </key-field>
                  </key-fields>
                  <read-ahead>on-load</read-ahead>
                  </ejb-relationship-role>
                  </ejb-relation>