[DB OJB Wiki] Updated: MixingMappingStrategies

[oj...@db.apache.org]

   Date: 2004-09-26T01:04:00
   Editor: JakobBraeuchi <jb...@gmx.ch>
   Wiki: DB OJB Wiki
   Page: MixingMappingStrategies
   URL: http://wiki.apache.org/db-ojb/MixingMappingStrategies

   no comment

Change Log:

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@@ -2,3 +2,29 @@
 There is a problem report in scarab:
 
 http://nagoya.apache.org/scarab/issues/id/OJB179
+
+
+The mapping strategy within a class hierarchy should be more flexible. OJB 1.0 does not allow mixing one-class-one-table with many-classes-one-table, because 'ojbConcreteClass?' is evaluated statically.
+
+OJB 1.1 will fix this issue, fixes are already in CVS. For the many-classes-one-table mapping the discriminator-column (old ojbConcreteClass?) can be defined in a special discriminator-descriptor. The optional attribute value can be used to set a user defined value to discriminate the classes. If 'value' is omitted, it defaults to the name of tha class from class-descriptor.
+
+ <class-descriptor
+       class="org.apache.ojb.broker.MultipleTableExtentAwareQueryTest?$ExtentA?"
+       table="EXTENT_TEST_A"
+ >
+       <discriminator-descriptor
+         column="class_name"
+         jdbc-type="VARCHAR"
+         value="MTEA_Ext_A"
+      /> 
+
+     <field-descriptor
+        name="objId"
+        column="OBJ_ID"
+        jdbc-type="INTEGER"
+        primarykey="true"
+        autoincrement="true"
+     />
+ </class-descriptor>
+]
+Another problem is the mapping on-class-multiple-tables, that is currently implemented using the 'super'-reference-descriptor. 

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