Hi all, i spent the whole weekend trying to adapt my project using OJB, here comes a
list of questions i really can't figure out answers in the mailing list archive. i
tested with these (w2k, jdk1.4.1, sun one studio, mysql, mm 2.0.14 jdbc driver)
public class User extends BusinessObject {
private String userId; // aggregated
private String password; // aggregated
private Timestamp creationDatetime; // aggregated
private Timestamp lastUpdateDatetime; // aggregated
private String name; // aggregated
private BusinessObjectList permissions; // aggregated
private String statusType; // aggregated
...
}
public class UserPermission extends BusinessObject {
private String name; // aggregated
private String value; // aggregated
...
}
where BusinessObject is a super class of our business entity of the following
definition
public abstract class BusinessObject implements Serializable, Cloneable {
private String primaryKey; // not updateable, direct dirty
private int sequenceNumber; // aggregated, direct dirty
private BusinessObject owner; // not updateable, direct dirty
private String ownerPrimaryKey;
...
}
mappings are done with these
<class-descriptor class="hk.com.mydomain.domain.security.User" table="USER">
<documentation>This is important documentation on the Article
class.</documentation>
<field-descriptor name="primaryKey" column="USER_UUID" jdbc-type="NUMERIC"
primarykey="true" autoincrement="true"
conversion="hk.com.mydomain.dao.util.StringBigDecimalConversion" />
<field-descriptor name="userId" column="USER_ID" jdbc-type="VARCHAR" />
<field-descriptor name="password" column="PASSWORD" jdbc-type="VARCHAR" />
<field-descriptor name="creationDatetime" column="CRE_DT" jdbc-type="TIMESTAMP"
/>
<field-descriptor name="lastUpdateDatetime" column="LAST_UPD_DT"
jdbc-type="TIMESTAMP" />
<field-descriptor name="name" column="NAME" jdbc-type="VARCHAR" />
<field-descriptor name="statusType" column="STATUS_TYPE" jdbc-type="CHAR" />
<collection-descriptor name="permissions"
element-class-ref="hk.com.mydomain.domain.security.UserPermission"
auto-retrieve="true" auto-update="true" auto-delete="true">
<orderby name="sequenceNumber"/>
<inverse-foreignkey field-ref="ownerPrimaryKey" />
</collection-descriptor>
</class-descriptor>
<class-descriptor class="hk.com.mydomain.domain.security.UserPermission"
table="USER_PERMISSION">
<documentation>This is important documentation on the Article
class.</documentation>
<field-descriptor name="primaryKey" column="USER_PERMISSION_UUID"
jdbc-type="NUMERIC" primarykey="true" autoincrement="true"
conversion="hk.com.mydomain.dao.util.StringBigDecimalConversion" />
<field-descriptor name="ownerPrimaryKey" column="USER_UUID" jdbc-type="NUMERIC"
/>
<reference-descriptor name="owner"
class-ref="hk.com.mydomain.domain.security.User">
<foreignkey field-ref="ownerPrimaryKey" />
</reference-descriptor>
<field-descriptor name="name" column="NAME" jdbc-type="VARCHAR" />
<field-descriptor name="value" column="VALUE" jdbc-type="VARCHAR" />
</class-descriptor>
essentially, it's a 1-M (User-UserPermission) mapping, with back-reference from
UserPermission to User implemented using owner association.
- first problem comes to me is my original BusinessObject class models primaryKey
using BigDecimal, do i have a way to keep it? i'm now using a self implemented
StringBigDecimalConversion class to do the conversion job that i find too indirect and
waste computation resource
- second question is when there is already owner association setup from UserPermission
to User, why OJB requires us to have a dedicated 'back-attribute' ownerPrimaryKey or
like this user
http://archives.apache.org/eyebrowse/ReadMsg?[EMAIL PROTECTED]&msgId=463861
is doing, having customerNo instead of customer object? this would introduce poor
design and navigatability problem.
- tried write up a code fragment to persist a uesrA->(user permission 1, user
permission 2) data structure, checked the backreferences 'owner' is set already,
however when persisted, the foreign key relation dropped, first thing ran thru my mind
is the ownerPrimaryKey that must have been missing when setting up the hierarchy. is
there any way we can have the back reference setup automatically?
- i tried followed this
http://archives.apache.org/eyebrowse/ReadMsg?[EMAIL PROTECTED]&msgId=500562
and wanted to see if any sql's generated but in vain, anybody can help?
- did anybody ever try ojb persisting data of encoding other than iso8859-1? i tried
to look for if any 'chinese' or 'japanese' in the mailing list and can't find any
questions related to 'em..
Best Regards,
Jemmee Yung
My Domain Consultant Limited
http://my-domain.com.hk/
