Code Generation : ManytoOne Relationship

rjain15 · **Joined:** Tue Feb 15, 2005 1:19 pm **Posts:** 10

I am trying to generate POJO's using hbm2java.
<hbm2java jdk5="true" ejb3="true"/>
I have two tables : Customer and Account, with a one to many relationship.

The database has the constraint defined, and in my jdbcconfiguration I have specified detectmanytomany="true"

But the generated code doesn't produce the correct methods: e.g. I am expecting
private Customer customer; and corrosponding get/set but it generates private String customerid. It is not generating the methods for the relationships.
So do I have specify in the reveng.xml the foreign key relationships?

regards
Rajesh

max · **Posted:** Thu Mar 22, 2007 1:15 pm

you don't have a db with proper foreign keys in it (or your driver does not support it at least)

rjain15 · **Joined:** Tue Feb 15, 2005 1:19 pm **Posts:** 10

I am using Apache Derby and using the JDBC Client Driver.
The hibernate.properties file has the following settings

## Derby
hibernate.dialect org.hibernate.dialect.DerbyDialect
hibernate.connection.driver_class org.apache.derby.jdbc.ClientDriver
hibernate.connection.url jdbc:derby://localhost:1527/sample;create=true

At the Database level, I can see the FK Constraint.
ALTER TABLE Account ADD CONSTRAINT Account_Customer FOREIGN KEY (CustomerId) REFERENCES Customer (id);

Any reasons why I cannot get this in the generated PO's. IS there any way to add DEBUG statments during generation, so I can see how the generator is working?

Thanx!
Rajesh

max · **Posted:** Thu Mar 22, 2007 4:15 pm

include log4j and enable debug logging and you should see alot ;)

rjain15 · **Joined:** Tue Feb 15, 2005 1:19 pm **Posts:** 10

I am not getting much information in the console logs (kind of what should I be looking for, seems there are some zip file error spitted by Ant, otherwise looks good).

I am trying to zero on why I am not getting the Foreign Key Relationships generated.
Has anyone generated for Apache Derby and can they share their reverse engineering file and the build script.

regards
Rajesh

rjain15 · **Joined:** Tue Feb 15, 2005 1:19 pm **Posts:** 10

Is the association generation in Reverse engineering not available?

See this thread
http://forum.hibernate.org/viewtopic.ph ... t=hbm2java

regards
Rajesh

rjain15 · **Joined:** Tue Feb 15, 2005 1:19 pm **Posts:** 10

Ok, I did run hbm2java with HSQL and Associations works. So Derby doesn't work. FYI... I hope it gets picked up as it is getting popular.

regards

klauz · **Posted:** Mon Apr 23, 2007 4:40 am

Hi,

while trying to reverse engineer an Oracle schema to produce jpa compliant annotations I found no relational information being generated into my pojos (using ANT with latest HT plugin jars 3.2.0.9a w/o eclipse).

I assume this is due to "wrong" data modelling.
In my scenario, I basically modelled two tables, MASTER and SLAVE,
of which MASTER carried the columns A (primary-key constraint), B (unique-key constraint) and C (some data)
and SLAVE was defined like X (primary-key constraint), Y (Foreign-key constraint) and Z (some data).

Y was related to B (FK), which does not work, at least with Oracle.
However, associating Y with A (FK) works pretty well.

Would you agree this is a faulty data modelling? Is there a chance this issue will be taken care of as a feature?

Take care
Klaus

max · **Posted:** Mon Apr 23, 2007 4:47 am

how about showing the table and foreign key dml - think it would be easier to follow then ;)

klauz · **Posted:** Mon Apr 23, 2007 10:40 am

Hi,

hope the below will help.

This will initially not work as described in my previous post.
Please observe the disparate foreign key constraints tagged with ***.

Code:

CREATE TABLE "KLAUZ"."MASTER" ("A" VARCHAR2(10 byte) NOT NULL, 
    "B" VARCHAR2(10 byte) NOT NULL, "C" LONG NOT NULL, 
    CONSTRAINT "MASTER_PK11177337506546" PRIMARY KEY("A") 
    USING INDEX  
    TABLESPACE "USERS" 
    STORAGE ( INITIAL 64K NEXT 0K MINEXTENTS 1 MAXEXTENTS 
    2147483645 PCTINCREASE 0) PCTFREE 10 INITRANS 2 MAXTRANS 255,
    CONSTRAINT "MASTER_UK21177337506546" UNIQUE("B") 
    USING INDEX  
    TABLESPACE "USERS" 
    STORAGE ( INITIAL 64K NEXT 0K MINEXTENTS 1 MAXEXTENTS 
    2147483645 PCTINCREASE 0) PCTFREE 10 INITRANS 2 MAXTRANS 255)
     
    TABLESPACE "USERS" PCTFREE 10 PCTUSED 0 INITRANS 1 MAXTRANS 
    255 
    STORAGE ( INITIAL 64K NEXT 0K MINEXTENTS 1 MAXEXTENTS 
    2147483645 PCTINCREASE 0) 
    LOGGING 

CREATE TABLE "KLAUZ"."SLAVE" ("X" VARCHAR2(10 byte) NOT NULL, "Y"
    VARCHAR2(10 byte) NOT NULL, "Z" LONG NOT NULL, 
*** 
    CONSTRAINT "SLAVE_FK81177337605734" FOREIGN KEY("Y") 
    REFERENCES "KLAUZ"."MASTER"("B"), 
*** 
    CONSTRAINT "SLAVE_PK11177337529750" PRIMARY KEY("X") 
    USING INDEX  
    TABLESPACE "USERS" 
    STORAGE ( INITIAL 64K NEXT 0K MINEXTENTS 1 MAXEXTENTS 
    2147483645 PCTINCREASE 0) PCTFREE 10 INITRANS 2 MAXTRANS 255)
     
    TABLESPACE "USERS" PCTFREE 10 PCTUSED 0 INITRANS 1 MAXTRANS 
    255 
    STORAGE ( INITIAL 64K NEXT 0K MINEXTENTS 1 MAXEXTENTS 
    2147483645 PCTINCREASE 0) 
    LOGGING 

Slightly modifying the dependent table's fk constraints and the generation will operate as expected (master ddl omitted / unchanged).

Code:

CREATE TABLE "KLAUZ"."SLAVE" ("X" VARCHAR2(10 byte) NOT NULL, "Y"
    VARCHAR2(10 byte) NOT NULL, "Z" LONG NOT NULL, 
***
    CONSTRAINT "SLAVE_FK31177338173718" FOREIGN KEY("Y") 
    REFERENCES "KLAUZ"."MASTER"("A"),
*** 
    CONSTRAINT "SLAVE_PK11177337529750" PRIMARY KEY("X") 
    USING INDEX  
    TABLESPACE "USERS" 
    STORAGE ( INITIAL 64K NEXT 0K MINEXTENTS 1 MAXEXTENTS 
    2147483645 PCTINCREASE 0) PCTFREE 10 INITRANS 2 MAXTRANS 255)
     
    TABLESPACE "USERS" PCTFREE 10 PCTUSED 0 INITRANS 1 MAXTRANS 
    255 
    STORAGE ( INITIAL 64K NEXT 0K MINEXTENTS 1 MAXEXTENTS 
    2147483645 PCTINCREASE 0) 
    LOGGING 

Take care,
Klaus

klauz · **Posted:** Wed May 16, 2007 10:16 am

light on this issue, please

mahincita · **Joined:** Mon Jul 02, 2007 6:29 pm **Posts:** 3

I am a little bit worried of reading all of this replies.........., so it means that hibernate tools does not work with derby to reflect his relations of foreign keys in the java classes and in the *.hbm.xml files?, it does not work at all?

max · **Posted:** Tue Jul 03, 2007 1:50 am

well looks to me that derby is not obeying the jdbc metadata spec.

oracle, ms sql, postgress, h2, hsqldb and even mysql reports foreign key constraints just fine (if the driver is recent enough).