if you run into trouble, you maybe need to patch PlatformDB2Impl class, because there was a check in of a fix by Matthias Roth after rc5.
Index: PlatformDb2Impl.java
===================================================================
RCS file: /home/cvs/db-ojb/src/java/org/apache/ojb/broker/platforms/PlatformDb2Impl.java,v
retrieving revision 1.7
retrieving revision 1.8
diff -u -r1.7 -r1.8
--- PlatformDb2Impl.java 9 Dec 2003 22:48:20 -0000 1.7
+++ PlatformDb2Impl.java 19 Dec 2003 18:01:10 -0000 1.8
@@ -98,9 +98,13 @@
{
return "drop sequence " + sequenceName;
}
-
- public String getLastInsertIdentityQuery(String tableName)
- {
- return "values IDENTITY_VAL_LOCAL() fetch first row only";
- }
+
+ public String getLastInsertIdentityQuery(String tableName)
+ {
+ // [EMAIL PROTECTED]
+ // the function is used by the org.apache.ojb.broker.util.sequence.SequenceManagerNativeImpl
+ // this call must be made before commit the insert cammand, so you
+ // must turn off autocommit by seting the useAutoCommit="2", "1" should work too
+ return "select IDENTITY_VAL_LOCAL() from sysibm.sysdummy1";
+ }
}
regards, Armin
Dirk Manske (Service Respond) wrote:
thank you both. you helped me a lot in understanding ojb. I'll give it a try.
Dirk
-----Ursprüngliche Nachricht-----
Von: Armin Waibel [mailto:[EMAIL PROTECTED] Gesendet: Donnerstag, 15. Januar 2004 18:06
An: OJB Users List
Betreff: Re: AW: AW: AW: AW: Two 1:N mappings to one table
Hi Dirk,
if you use Identity columns from database you can't use the default SequenceManager (SequenceManagerHighLowImpl). Have a look in http://db.apache.org/ojb/sequencemanager.html#nativeSequenceManager
> can all do for me. In the repository-user.xml I set every pk column with
primarykey="true" and autoincrement="true" for "declarative reasons",
When using SequenceManagerNativeImpl you have to set access="readonly" too.
regards, Armin
Dirk Manske (Service Respond) wrote:
hm. our db2 database tables are configured with an autoincrement for the primary keys by default. (for exampl: activityId INTEGER NOT NULL GENERATED BY DEFAULT AS IDENTITY (STARTS WITH 1, INCREMENT BY 1, NO CACHE, PRIMARY KEY). this is my first time using ojb. Meanwhile I get aware of what ojb can all do for me. In the repository-user.xml I set every pk column with primarykey="true" and autoincrement="true" for "declarative reasons", because I thought OJB must get to know which columns in db2 are set to pk's... Now I am wondering if the best practice would be to set up the physical database with no pk's, fk's etc at all and declare everything in the repository and let ojb control
it?
Furthermore I already declared a high/low sequence manager in the repository without actually knowing what I was doing (I copied it from somewhere). So please could you tell me what happend behind the scenes? I guess OJB generated an id and tried to store it with the object but then,
db2 overwrote the id via autoincrement. After the second store operation, OJB looks for its generated id, cannot find it and stores it as a new activity instead of updating it. hm. what would be the best advised? I haven't asked yet but I am pretty sure that I am not allowed to set autoincrement off in db2, because other apps might use these tables as well...
-----Ursprüngliche Nachricht----- Von: Brian McCallister [mailto:[EMAIL PROTECTED] Gesendet: Donnerstag, 15. Januar 2004 16:44 An: OJB Users List Betreff: Re: AW: AW: AW: Two 1:N mappings to one table
Ah hah! You are allowing DB2 to add the ID via a trigger, aren't you? OJB doesn't play super nicely with the database doing that for it behind the scenes, unfortunately. If you are allowed, try using one of the OJB auto increment modules. I suggest the one that pulls from a db sequence if that is what you are using in DB2 now. Basically it will have OJB pull from the sequence and populate the id prior to the insert so
that OJB knows the id.
-Brian
On Jan 15, 2004, at 10:25 AM, Dirk Manske (Service Respond) wrote:
Unfortunately I cannot provide a testcase for this. But in general, after I stored the activity with pm.store(venture), the second operation
pm.store(person) should automagically update activity and not save it as a new entry, right? Or will it be only updated, if the activityId is known?
Because I use DB2 with autoincrement for pk's and therefore on the first store operation I have no id yet. hm. any idea?
Dirk
-----Ursprüngliche Nachricht----- Von: Brian McCallister [mailto:[EMAIL PROTECTED] Gesendet: Donnerstag, 15. Januar 2004 04:28 An: OJB Users List Betreff: Re: AW: AW: Two 1:N mappings to one table
Hmm, fun one. I suspect you may have run into the weird edge case.
I don't have an immediate answer on this -- need to play and dig.
Anyone else hit this before? Any chance you can create a unit test that demonstrates the behavior? If so send it to me and I'll check it in and dig in (or start prodding).
-Brian
On Jan 14, 2004, at 1:21 PM, Dirk Manske (Service Respond) wrote:
Hi Brian,
exactly. Due to copy & paste I assigned a wrong column to the attribute activityId in class Person. But know I experience the problem, that each created activity is stored twice (with different id's). I mean, I know why, I add activity once to the 'person collection' and to the 'venture collection' and do then
pm.store(venture) and pm.store(person). I guess I have to follow a different approach?! Say, store first venture, then retrieve activity to store it with person? or how does it work?
thx, Dirk
-----Ursprüngliche Nachricht----- Von: Brian McCallister [mailto:[EMAIL PROTECTED] Gesendet: Mittwoch, 14. Januar 2004 18:33 An: OJB Users List Betreff: Re: AW: Two 1:N mappings to one table
It sounds like there is actually a problem in the mapping from class -> table where the activityId is listed.
Any chance you could post the full mapping for these classes, along with the database schema?
-Brian
On Jan 14, 2004, at 11:33 AM, Dirk Manske (Service Respond) wrote:
Hi,
yes, i am using pb. Setting auto-retrieve="true" in the collection-descriptor has not the desired effect, I still get the following two strange error messages:
within browser it shows a null pointer execption for Venture when it tried to retrieve all venture objects associated with activity and in the tomcat console I get a SQL Exception for class PERSON, state that activityId is not valid in the context where it is used (db2 database error message).
When I set auto-retrieve="false" for PERSON in the reference-descriptor of class ACTIVITY, the venture objects are retrieved. no error message.
everything works fine, except - of course I have no person objects then.
any idea?
Dirk
-----Ursprüngliche Nachricht----- Von: Brian McCallister [mailto:[EMAIL PROTECTED] Gesendet: Mittwoch, 14. Januar 2004 15:13 An: OJB Users List Betreff: Re: Two 1:N mappings to one table
Mapping to 1:N's to the same table is fine, heack mapping 1:N's form one class to itself multiple times works fine.
From looking at your configs I will venture that you are using the PB API and one of the collections isn't loading -- try setting auto-retrieve on the collections, or (these are exclusive) try using the ODMG API (which will retrieve them automagically)
-Brian
On Jan 13, 2004, at 7:58 PM, Dirk Manske wrote:
Hi,
how can I map two tables with each having a 1:N relation to the same table?
I always get a null pointer exception for class Person.
I have three tables:
PERSON with a 1:N relation to ACTIVITY
and
VENTURE with a 1:N relation to ACTIVITY
Table PERSON and VENTURE both references activityId from table ACTIVITY. In the repository-user.xml for each table which relates to ACTIVITY the collection-descriptor is setup
for table VENTURE:
<collection-descriptor
name="allAssignedActivities"
element-class-ref="de.plato.Activity"
orderBy="activityId"
sort="DESC"
auto-update="true" >
<inverse-foreignkey field-ref="ventureId" /> </collection-descriptor>
and for table PERSON:
<collection-descriptor
name="allAssignedActivities"
element-class-ref="de.plato.Activity"
orderBy="activityId"
sort="DESC"
auto-update="true" >
<inverse-foreignkey field-ref="personId" /> </collection-descriptor>
for ACTIVITY, both tables are referenced:
<reference-descriptor name="person"> class-ref="de.plato.Person" refresh="true" auto-retrieve="true"> <foreign-key field-ref="personId" />
and
<reference-descriptor name="venture"> class-ref="de.plato.Venture" refresh="true" auto-retrieve="true"> <foreign-key field-ref="ventureId" />
Unfortunately, this does not work. What do I have to do?
thx, Dirk
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