Ronald, Please see inline... ----- Original Message ----- From: Ronald Rudy <[EMAIL PROTECTED]> Date: Monday, May 2, 2005 2:47 pm Subject: RE: RE: [castor-dev] many-to-many mapping..
> That doesn't seem to make sense. ObjectTwo doesn't only have to be > associated with ObjectOne types, but many other types as well. > It's a > common attribute of types in this system. > > For example, suppose ObjectTwo is color while ObjectOne is a car. > There is > a many-to-many relationship between the two, even though it only > makes sense > to associate them one way. Perhaps you also want to add fruits to the > database and associate them in a many-to-many fashion with colors. > Would > the color type now have to support a reverse relationship between > the cars > AND the fruits? > With regards to Castor's (current) behavior, you should specify many-to-many relations to both cars and fruits in the color's mapping. Of course, you're going to specify cars and fruits fileds in color as lazy loaded, so when you load a color, not all of the cars and fruits using that color are loaded too. > -Ron > > -----Original Message----- > From: [EMAIL PROTECTED] [EMAIL PROTECTED] > Sent: Monday, May 02, 2005 8:22 AM > To: [email protected] > Subject: Re: RE: [castor-dev] many-to-many mapping.. > > > Ronald, > I think it's required to map both sides of the relation. > Try doing it. > > > Regards, > Emir > > > ----- Original Message ----- > From: Ronald Rudy <[EMAIL PROTECTED]> > Date: Monday, May 2, 2005 2:23 pm > Subject: RE: [castor-dev] many-to-many mapping.. > > > Here is my mapping: > > > > <class name="com.xyz.ObjectOne" identity="oneId" > > key-generator="SEQUENCE"> > > <description>"First of Many-to-Many Object"</description> > > <map-to table="object_one"/> > > <cache-type type="none"/> > > <field name="oneId" type="integer"> > > <sql name="object_one_id" type="integer"/> > > </field> > > > > ... > > > > <field name="objectTwo" type="com.xyz.ObjectTwo" > > collection="arraylist"> > > <sql name="object_two_id" many- > table="objectone_objecttwo_map"> many-key="object_one_id" key- > generator="SEQUENCE" /> > > </field> > > </class> > > > > > > <class name="com.xyz.ObjectTwo" identity="twoId" > > key-generator="SEQUENCE"> > > <description>"Second of Many-to-Many Object"</description> > > <map-to table="object_two"/> > > <cache-type type="none"/> > > <field name="twoId" type="integer"> > > <sql name="object_two_id" type="integer"/> > > </field> > > > > ... > > > > </class> > > > > > > I didn't include a reverse mapping from the ObjectTwo -> ObjectOne > > because I > > don't have/need a property on the com.xyz.ObjectTwo class to get > > back to > > ObjectOne. > > > > The mapping table objectone_objecttwo_map has three relevant fields: > > > > primary key of the mapping table itself > > foreign key of 'object_one' record this is associated with > > foreign key of 'object_two' record this is associated with > > > > -Ron > > > > -----Original Message----- > > From: Werner Guttmann [EMAIL PROTECTED] > > Sent: Monday, May 02, 2005 8:12 AM > > To: [email protected] > > Subject: AW: [castor-dev] many-to-many mapping.. > > > > > > Ronald, > > > > there's no need to define a mapping object, as your many-to-may > > relationwill be handled automatically by Castor. And this should > > by definition > > include the handling of the keys in the mapping table. It looks > > like you > > have got the mapping slightly wrong, so can you please post the > > relevantmapping section, the DDL used to create the tables in > > question and some > > information about the classes engaging in such mapping ? > > > > Werner > > > > -----Urspr�ngliche Nachricht----- > > Von: Ronald Rudy [EMAIL PROTECTED] > > Gesendet: Montag, 02. Mai 2005 14:08 > > An: [email protected] > > Betreff: [castor-dev] many-to-many mapping.. > > > > > > I have configured Castor to support a many-to-many relationship > > between two > > types of objects, but I'm getting an error. This is because the > > mappingtable itself (in Oracle) contains a primary key of its own, > > and this is not > > automatically assigned by Castor. So when a new relationship is > > created,this primary key is null and the database throws an error. > > > > I don't have control over the database schema - is there any way to > > configure Castor to recognize that the configured many-table has a > > primarykey and the key can be created using the sequence key > > generator? (the > > sequence key generator works fine for everything else) Or am I > > going to be > > forced to create a "map" object that handles the relationship > > 'manually'? > > -Ron > > > > > > > > > >
