Null Field in Composite Primary Key

Can you have a column be part of a primary key and be nullable?
I have a table of three fields and I want them all to be part of a primary key, because I need all three columns to reference a unique row. However, one of the fields references a field in another table which can be null. Is there anyway I can achieve this?

Any columns included in the primary key will be converted to not NULLable as necessary, so, no, you cannot have a NULLable column as part of a primary key.
You can, however, create a unique constraint that includes a NULLable column as part of the composite key.

Similar Messages

Null value in Composite Primary key

Hi,
I have a requirement where I need to identify each record based on 4 columns. I though that I could achieve the same by imposing a composite primary key based on all the 4 columns. But any one of the column can be null at anytime. Can I still impose a composite primary key? i.e., if I create a composite primary key based on 4 columns, can any one of the column be null?
Your help would be more appreciated.

No, you can't
By definition a Primary Key is NOT NULL
SQL> drop table t
2 /
Table dropped.
Elapsed: 00:00:00.03
SQL>
SQL> create table t
2 (col1 number null
3 ,col2 number null
4 ,col3 number null
5 ,col4 number null
6 ,constraint tpk primary key (col1, col2, col3, col4)
7 )
8 /
Table created.
Elapsed: 00:00:00.03
SQL>
SQL> desc t
Name                                                              Null?    Type
COL1                                                              NOT NULL NUMBER
COL2                                                              NOT NULL NUMBER
COL3                                                              NOT NULL NUMBER
COL4                                                              NOT NULL NUMBER
SQL>

Null in Composite Primary Key and "Primary keys must not contain null"

Hello all.
I'm a newbie concerning to JPA/EJB3, but I was wondering if toplinks doesn't support composite primary keys with null in some field (something perfectly right in any RDBMS).
I used JDeveloper (I'm using Oracle 10g database and JDeveloper 10.1.3.2.) wizards to generate JPA classes and I checked out generated files (with annotations), so they should be right (by the way, other O-R mappings for my model are working right, but this one).
I'm getting the next error:
Exception Description: The primary key read from the row [DatabaseRecord(
     TSUBGRUPOSLDI.CD_GRUP => 01
     TSUBGRUPOSLDI.CD_SUBGRUP => null
     TSUBGRUPOSLDI.CG_POBL => 058
     TSUBGRUPOSLDI.CG_PROV => 28
     TSUBGRUPOSLDI.DSCR => Sanidad)] during the execution of the query was detected to be null. Primary keys must not contain null.
Compound primary key is (CD_GRUP, CD_SUBGRUP). No foreign keys, no joins (only a NamedQuery: "select o from ..."). It's the simplest case!
I checked out that everything runs ok if there's no "null" value in CD_SUBGRUP.
After some research (this and other forums) I'm beginning to believe that it's not supported, but not sure.
Am I doing sth wrong? If not, what is the reason to not support this? Will it be supported in the future?
Thanks in advance.

Null is a special value and in many databases is not comparable to another null value (hence the isNull operator) and may pose problems when used to uniquely identify an Entity. TopLink does not support null values within a composite PK. As the nullable column is most likely not designated as a PK within your database table (many databases do not allow this) I recommend updating the Entity PKs to match that of the database.
--Gordon

In which case composite primary key allows NULL values in it

Hi to all
In what case composite primary key allows nulls in it.
Let us suppose, I created a composite primary key with 2 attributes.
CREATE TABLE sample
BNK_Id NUMBER(6),
BNK_Name VARCHAR2(20),
CONSTRAINT BNK_Id_Name_PK PRIMARY KEY(BNK_Id,BNK_Name)
When it allows null values in it.
thanks in advance

Are you sure that your instructor was not talking about unique keys? As Solomon said, a primary key always implies not null on all of the columns of the PK. However a unique key does not automatically imply not null, and can have nulls in a column as long as the values in the populated columns are unique.
SQL> create table test (
2     id number,
3     pid number,
4     descr varchar2(10));
Table created.
SQL> alter table test add constraint test_unq
2     unique (id, pid);
Table altered.
SQL> insert into test values (1, null, 'desc1');
1 row created.
SQL> insert into test values (2, null, 'desc2');
1 row created.
SQL> insert into test values (2, null, 'fail1');
insert into test values (2, null, 'fail1')
ERROR at line 1:
ORA-00001: unique constraint (OPS$ORACLE.TEST_UNQ) violatedJohn

Can a composite primary key column be null

Hi All,
It will be a silly question but still I would like to ask can a composite primary key column be null?
Thanks,
Rafi.

Rafi,
Why you think it would be allowed?
SQL> drop table test purge;
drop table test purge
ERROR at line 1:
ORA-00942: table or view does not exist
SQL> create table test as select * from dba_objects;
Table created.
SQL> alter table test add primary key(object_id, owner);
Table altered.
SQL> insert into test(object_id, owner) values(null, 'aman');
insert into test(object_id, owner) values(null, 'aman')
ERROR at line 1:
ORA-01400: cannot insert NULL into ("SYS"."TEST"."OBJECT_ID")
SQL> insert into test(object_id, owner) values(1,null);
insert into test(object_id, owner) values(1,null)
ERROR at line 1:
ORA-01400: cannot insert NULL into ("SYS"."TEST"."OWNER")
SQL>HTH
Aman....

How to Alter any table to make some fields Composite Primary Key

I need to Alter Table to make some fields Composite Primary Key.
Is it possible to do this ?
Please give any example.
Regards,
AgrawalV

Agrawal
If you are looking for an example to create a composite primary key, here you are.
sql> Alter Table myTable add constraint pk_myTable primary key(col1, col2, ...coln) ;
where
pk_myTable is the name of the primary key constraint,
myTable is the name of the table that you want to create a constraint on and
col1...coln are the column names in the table <myTable)

Composite Primary Key Error

I am using Sun One App Server PE8.
I have a class with a composite primary key field. When I place the following method in my Home interface:
public MyEjb findByPrimaryKey(MyEjbPrimaryKey pk) throws FinderException, RemoteException;I get the following error when deploying:
ejbFindByPrimaryKey(EjbPrimaryKey) is already defined in MyEjb1368202910_ConcreteImpl
    public MyEjbPrimaryKey ejbFindByPrimaryKey (MyEjbPrimaryKey key)However, If i remove this method from the Home interface, i get the following error when running the verification tool:
Error: No single arg findByPrimaryKey(PrimaryKeyClass) method was found in home interface class [ MyEjb ].However, I can still deploy the EAR successfully.
Another related symptom of this problem, is if I include the following method in my Home interface:
public MyEjb findByPrimaryKey(String pkField1, String pkField2) throws FinderException, RemoteException;And call this method, I get the following exception at runtime:
java.rmi.RemoteException: Bean class for ejb [MyEjb] does not define a method corresponding to [Home] interface method [public abstract MyEjb MyEjbHome.findByPrimaryKey(java.lang.String,java
.lang.String) throws javax.ejb.FinderException,java.rmi.RemoteException]I get these same problems with all EJB's that use composite keys. Has anyone else had this problem?
Thanks
toby

This is a CMP bean, with no ejbFindByPrimaryKey in the Bean class. Below, i have included the Home interface and the Bean class (with unneccessary code removed)
Thanks for looking at this for me.
BEAN CLASS
package lands.mc.bus.prod;
import java.rmi.*;
import java.util.*;
import javax.ejb.*;
public abstract class TopoMapBean implements EntityBean
private EntityContext entity;
public TopoMapBean()
public void setEntityContext(EntityContext ctx)
    entity = ctx;
public void unsetEntityContext()
    entity = null;
public TopoMapPrimaryKey ejbCreate(String mapName, String mapNumber, String mnemonic,String edition, String scale)
throws CreateException
    // call setters...
    return null;
public void ejbPostCreate( String mapName,
                                               String mapNumber,
                                         String mnemonic,
                                         String edition,
                                         String scale )
removed set/get methods
public void ejbStore() {}
public void ejbLoad() {}
public void ejbActivate() {}
public void ejbPassivate() {}
public void ejbRemove() {}
}HOME INTERFACE
package lands.mc.bus.prod;
import java.rmi.*;
import java.util.*;
import javax.ejb.*;
public interface TopoMapHome extends EJBHome
public TopoMap create(String mapName,
                        String mapNumber,
                        String mnemonic,
                        String edition,
                        String scale
throws CreateException, RemoteException;
public TopoMap findByPrimaryKey(String mapNumber, String edition) throws FinderException, RemoteException;
// doesnt deploy with this signature
// public TopoMap findByPrimaryKey(TopoMapPrimaryKey pkey) throws FinderException;
// have to use this method instead of findByPrimaryKey(String, String) above
public TopoMap findTopoMap(String mapNumber, String edition) throws FinderException, RemoteException;

How to persist an entity with Composite primary key

Problem Statement:-
Entity A have many to one relation with Entity C
Entity B have many to one relation with Entity C
Entity C have a composite primary key of (Entity A PK & Entity B PK)
A --< C
B --< C
the entites are automatic generated by Dali tool
@Entity
public class C implements Serializable
     @EmbeddedId
     private C.PK pk;
     private int attribute;
     //Code
     @Embeddable
     public static class PK implements Serializable
          public int A_Id;
          public int B_Id;
          //Code
@Entity
public class A implements Serializable
     @Id
     private int AId;
     @OneToMany
     private Set<C> C_Collection;
     //Code
@Entity
public class B implements Serializable
     @Id
     private int BId;
     @OneToMany
     private Set<C> C_Collection;
     //Code
i made a session Bean which add a new entity C
Session
     A a = em.find(A.class, AId);
     B b = em.find(B.class, BId);
     C c = new C();
     C.PK pk = new C.PK();
     pk.AId(a.getID());
     pk.BId(b.getID());
     c.setPk(pk);
     c.setA(a);
     c.setB(b);
     c.setAttribute(12);
     em.persist(c);
when running this code an exception is raised
Exception [TOPLINK-4002] (Oracle TopLink Essentials - 2006.8 (Build 060830)): oracle.toplink.essentials.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: Unknown column 'A_ID' in 'field list'Error Code: 1054
Call:INSERT INTO C (attribute, Aid, A_ID, B_ID, Bid) VALUES (?, ?, ?, ?, ?)
     bind => [2, 6, 6, 1, 1]
this is logic as Table "C" has only 3 coloumns only "attribute" , "Aid" , "Bid"
but the mapping is different as it adds the composite PK attributes to the insert statement
if there is a sample code or how to solve this issue it would be great

Hello Juwen,
The problem is you are registering an object, assigning it a null pk, and then commiting the uow/transaction. TopLink uses registered objects to keep track of changes you make inorder to persist those changes on commit. So the simple fix is to not commit the UnitOfWork - call release() on it instead.
Another solution is to use the session copyObject api. The simple form that only takes an object will work similar to registering the object as it will copy all persistent attributes but it will leave the primary key null. You can also use this method to specify a copyPolicy to customize the process. Using this method will be a bit more efficient, since a UOW makes both a working copy and a back up copy of objects registered, inorder to keep track of changes. Using the copyObject api will only make a single copy.
Best Regards,
Chris

Update enrolled table which has 6 composite primary key

Hi Everyone,
I am trying to update a grade column in table called enrolled which has 6 composite primary key column including SID, TERMYEAR, FACCODE, DEPCODE, COURSENO, SECNO and 2 extra column including GRADE, IDD all of them are of type VARCHAR2 as describe below:
To update this table I used the command below:
UPDATE enrolled
SET grade = :COURSE_BLOCK.GRADE_TEXT
WHERE IID = :GLOBAL.logUserid
AND SID = :COURSE_BLOCK.SID_TEXT
AND FACCODE = :COURSE_BLOCK.FACULTY_TEXT
AND DEPCODE = :COURSE_BLOCK.DEPARTMENT_TEXT
AND COURSENO = :COURSE_BLOCK.COURSE_TEXT
AND SECNO = :COURSE_BLOCK.SECTION_TEXT;
Note: the :GLOBAL.logUserid is a global variable that I assigned the user id when the user log on to the application.
When I run the application and fill out the form in order to update the table this doesn't update the table and if I use SQL*PLUS as well with the values that I use for the form to update the table I get message: o rows updated
Can Someone help please?

Here is the solution.
The problem:
The problem was that the enrolled table was designed in a way that a student can enrolled in the lecture(LEC type column) and Laboratory(LAB type column). When a student is given a grade, it is given a grade for the course 100 (eg: 03-60-100) this course has a lecture and lab. this course belong to the faculty code 03(science) department 60 (computer Science) so when a student register to a course, will register to a lecture and a lab but he will receive a grade for the course 100 lec in this case Oracle couldn't update the table because there was two column with course 100 for that particular student Id
The solution:
There are many solution I believe but my quickest solution is when a student register to the course by default is given a grade 'I' means Incomplete then when the instructor add the grade, he can just update a grade from incomplete to the final grade (eg A) now the code will be to get only the course 100 that has grade and discard that doesn't have grade this means that I need only to make sure that the WHERE Clause grade is not null shown below.
UPDATE enrolled
SET grade = BLOCK_NAME.FIELD_NAME
WHERE grade IS NOY NULL
AND IID = BLOCK_NAME.FIELD
AND faccode = BLOCK_NAME.FIELD
AND depcode = BLOCK_NAME.FIELD
AND courseno= BLOCK_NAME.FIELD_NAME
NAD secno = BLOCK_NAME.FIELD_NAME
AND SID = BLOCK_NAME.FIELD_NAME

Error While Deploying A CMP Entity Bean With A Composite Primary Key

Hello all,
I have a problem deploying CMP Entity beans with composite primary keys. I have a CMP Entity Bean, which contains a composite primary key composed of two local stubs. If you know more about this please respond to my post on the EJB forum (subject: CMP Bean Local Stub as a Field of a Primary Key Class).
In the mean time, can you please tell me what following error message means and how to resolve it? From what I understand it might be a problem with Sun ONE AS 7, but I would like to make sure it's not me doing something wrong.
[05/Jan/2005:12:49:03] WARNING ( 1896):      Validation error in bean CustomerSubscription: The type of non-static field customer of the key class
test.subscription.CustomerSubscriptionCMP_1530383317_JDOState$Oid must be primitive or must implement java.io.Serializable.
     Update the type of the key class field.
     Warning: All primary key columns in primary table CustomerSubscription of the bean corresponding to the generated class test.subscription.CustomerSubscriptionCMP_1530383317_JDOState must be mapped to key fields.
     Map the following primary key columns to key fields: CustomerSubscription.CustomerEmail,CustomerSubscription.SubscriptionType. If you already have fields mapped to these columns, verify that they are key fields.Is it enough that a primary key class be serializable or all fields have to implement Serializable or be a primitive?
Please let me know if you need more information to answer my question.
Thanks.
Nikola

Hi Nikola,
There are several problems with your CMP bean.
1. Fields of a Primary Key Class must be a subset of CMP fields, so yes, they must be either a primitive or a Serializable type.
2. Sun Application Server does not support Primary Key fields of an arbitrary Serializable type (i.e. those that will be stored
as BLOB in the database), but only primitives, Java wrappers, String, and Date/Time types.
Do you try to use stubs instead of relationships or for some other reason?
If it's the former - look at the CMR fields.
If it's the latter, I suggest to store these fields as regular CMP fields and use some other value as the PK. If you prefer that
the CMP container generates the PK values, use the Unknown
PrimaryKey feature.
Regards,
-marina

Urgent - ESB: DB Adapter with composite primary keys no returning any data

I have a DB Adapter in the ESB that inserts/updates/selects data to/from a table with 2 columns as primary keys, but table has several columns.
1. Initially, the db table had constraints for the composite primary key, The DB adapter had valid data coming in, but no result data.
2. Then I removed the db constraints on the composite primary key, and selected the 2 columns in the DB adapter wizard. Still, valid data is going in, since I am outputing to a file prior to call this node, but no result data is appearing. The result XML is empty.
Do I need to do something in Toplink for this?
The table spec is below. the ACCT_FIELD and ACCT_CODE columns make up the composite primary key.
CREATE TABLE AFF_DATA_SYNC
ACCT_FIELD NUMBER NOT NULL,
ACCT_CODE VARCHAR2(16) NOT NULL,
ACCT_EXISTS_FLAG VARCHAR2(1),
SAVE_ACCT_SEG_XML CLOB,
LAST_UPDATE_DATE DATE
The following xml is the request to the DB adapter:
<top:AffDataSyncReadDBAdapterSelect_accountField_accountCodeInputParameters xmlns:top="http://xmlns.oracle.com/pcbpel/adapter/db/top/AffDataSyncReadDBAdapter">
<top:accountField>8</top:accountField>
<top:accountCode>0003888</top:accountCode>
</top:AffDataSyncReadDBAdapterSelect_accountField_accountCodeInputParameters>
Log output:
JCA: esb:///ESB_Projects/STRIPES-AFF-Data-Intg_AFF-Data-Integration/AffDataSyncReadDBAdapter.wsdl [ AffDataSyncReadDBAdapter_ptt::AffDataSyncReadDBAdapterSelect_accountField_accountCode(AffDataSyncReadDBAdapterSelect_accountField_accountCode_inparameters,Af
DataSyncWipCollection) ] - No XMLRecord headers provided
JCA: <oracle.tip.adapter.db.DBInteraction executeOutboundRead> Executing query with arguments [8, 0003917]
JCA: <oracle.tip.adapter.db.TopLinkLogger log> SELECT ACCT_FIELD, ACCT_CODE, ACCT_EXISTS_FLAG, SAVE_ACCT_SEG_XML, LAST_UPDATE_DATE FROM
AFF_DATA_SYNC_WIP WHERE ((ACCT_FIELD = ?) AND (ACCT_CODE = ?))
bind => [8, 0003888]
JCA: <oracle.tip.adapter.db.DBInteraction executeOutboundRead> Read the following objects: []
Message was edited by:
user589357
Message was edited by:
user589357
Message was edited by:
user589357
Message was edited by:
user589357

The Toplink has no errors. Now I changed my table with only a single primary key, but for some reason, I am still getting no data.
JDeveloper 10.1.3.3 / SOA Suite (only using ESB) 10.1.3.3 with Oracle DB 10g 10.2.0.3.
1. What does No XMLRecord headers found mean?
2. Notice the last log item; Read ... []
Here are the log contents:
Invoking next service "AffDataSyncReadDBAdapterSelect_recordId" with payload :
<top:AffDataSyncReadDBAdapterSelect_recordIdInputParameters xmlns:top="http://xmlns.oracle.com/pcbpel/adapter/db/top/AffDataSyncReadDBAdapter">
<top:recordId>80003888</top:recordId>
</top:AffDataSyncReadDBAdapterSelect_recordIdInputParameters>
JCA: esb:///ESB_Projects/STRIPES-AFF-Data-Intg_AFF-Data-Integration/AffDataSyncReadDBAdapter.wsdl [ AffDataSyncReadDBAdapter_ptt::AffDataSyncReadDBAdapterSelect_recordId(AffDataSyncReadDBAdapterSelect_recordId_inparameters,AffDataSyncWipCollection)
] - No XMLRecord headers provided
JCA: esb:///ESB_Projects/STRIPES-AFF-Data-Intg_AFF-Data-Integration/AffDataSyncReadDBAdapter.wsdl [ AffDataSyncReadDBAdapter_ptt::AffDataSyncReadDBAdapterSelect_recordId(AffDataSyncReadDBAdapterSelect_recordId_inparameters,AffDataSyncWipCollection)
] - Starting JCA LocalTransaction
JCA: esb:///ESB_Projects/STRIPES-AFF-Data-Intg_AFF-Data-Integration/AffDataSyncReadDBAdapter.wsdl [ AffDataSyncReadDBAdapter_ptt::AffDataSyncReadDBAdapterSelect_recordId(AffDataSyncReadDBAdapterSelect_recordId_inparameters,AffDataSyncWipCollection)
] - Invoking JCA Outbound Interaction
JCA: <oracle.tip.adapter.db.DBInteraction executeOutboundRead> executing the NamedQuery: AffDataSyncReadDBAdapter.AffDataSyncWip.AffDataSyncReadDBAdapterSelect
JCA: <oracle.tip.adapter.db.DBInteraction executeOutboundRead> Parsing header record element.
JCA: <oracle.tip.adapter.db.TopLinkLogger log> client acquired
JCA: <oracle.tip.adapter.db.DBInteraction executeOutboundRead> Executing query with arguments [80003888]
JCA: <oracle.tip.adapter.db.TopLinkLogger log> SELECT RECORD_ID, ACCT_FIELD, ACCT_CODE, ACCT_EXISTS_FLAG, SAVE_ACCT_SEG_XML, LAST_UPDATE_DATE
FROM AFF_DATA_SYNC_WIP WHERE (RECORD_ID = ?)
bind => [80003888]
JCA: <oracle.tip.adapter.db.DBInteraction executeOutboundRead> Read the following objects: []
Message was edited by:
user589357
Message was edited by:
user589357

Composite primary key and InputSelect

Hi
I have a jsp page where I have an InputSelect list that display the on of the field of a composite primary key.
What I what is to pass the second field of the primary key to my submit page without letting the user see that field.
<tr>
<td>Projekt</td>
<td>
<jbo:InputSelect multiple="false"
datasource="ds"
dataitem="ProjektId"
displaydatasource="proid"
displaydataitem="ProjektId"
displayvaluedataitem="ProjektId" />
</td>
</tr>
<tr>
<td></td>
<td>
<jbo:InputHidden datasource="ds"
dataitem="Kundenr" ></jbo:InputHidden>
</td>
</tr>
How can I automaticly give this hidden field it's value.
With kind regards Arnar Dagsson

How to implement this?
A has one to many relation ship with B
TABLE A
key A1 (primary key)
data A2
data A3
fkey B2 --> @OneToManyShouldn't this be (it is composite):
TABLE A
key A1 (primary key)
data A2
data A3
fkey B1 --> @OneToMany
fkey B2 --> @OneToMany
>
TABLE B
key B1 (primary)
key B2 (primary) <--- @ManyToOne
data B3
Tried to use @OneToMany and @ManyToOne but complains
about
@JoinColumns etc. Is this possible at all?If you can avoid having composite primary keys
Take a look at this message for my answer
http://forum.java.sun.com/thread.jspa?threadID=764754&messageID=4366595#4366595
Hope it helps

Composite Primary key & Primary key questions

Background:
1.5 TB data warehouse. All tables use at least a 3 column composite Primary key. Most use 3. col1||col2||col3 to achieve uniqueness.
col1= very low cardinality. 99% of the values are '0'
col2 = high cardinality. (SSN's, loaded monthly)
col3 = low cardinality. (monthly sequence number used for partitioning)
From what I've read, the first column used in a composite primary key also receives its own index. If that is correct, then the primary key being used is losing its effectiveness by putting a very low cardinality column as the first column of the Primary key. By moving col2 to the first position of the composite key, I would be obtaining an index on SSN which would be much more useful. (Please correct me if I'm wrong) Or since the index would be so large anyway, the CBO would just do full table scans which is what I'm trying to get away from.
This Primary key is used to ensure uniqueness during loads. Other than that, it really has no purpose and is never queried by the user. (WHERE col1||col2||col3 = xxxxxxxxx)
As a DBA, I see this massive tablespace for holding the primary keys now reaching in excess of 157 GB and it seems like such a waste of space. The problem I'm running across is how to ensure uniqueness during the loads w/o having to store the unique values. (the 157 GB) If I drop the PK's, then create unique indexes just for the loads, then the unique index would be generated against the entire table, which would take forever.
If you create a local index (what I want in the end) it still has to create the index for all previous partitions (250+ partitions). You can't create a specific 'local' index on a partition. You create a local index on the table and when a new partition is added, the index is then added as well. That's what I want to do with some of my fields like SSN but for loading purposes, this isn't going to help me.
I need a way to ensure uniqueness during a monthly load of a new partition (col1||col2||col3) but w/o having to store these values for eternity. Right now it's the primary key, so it has to be stored. I hope I'm making sense here. Any ideas?

I think you need some clarification about the index supporting the primary key.
The primary key is unique - the database will enforce this for you.
All of the columns in the primary key are in the index that enforces the key (not just the first column).
Usually this index is a unique index, but you can have a non-unique index supporting a primary key.
I'm a little confused with some of your other statements
how to ensure uniqueness during the loads w/o having to store the unique valuesIf you don't store the value how do you know it is unique?
Did you mean that you don't want to store the key values in both the table and the index?
You may want to consider making col3 (the partition key) the leading column of the index, so you can create a local (instead of global) PK index.
I wouldn't worry too much about col1 (the column full of mostly zeros) - numbers are stored variable length. A NUMBER(38) that holds a zero takes no more space than a NUMBER(1) that holds a zero.

Composite primary key in ejb

Hi all,
I am new to ejb. I am trying to create a BMP bean for a particular table which is having composite primary key. I made a primary key class for that and I have done all the important things required for creating such a class viz,
1) implement java.io.Serializable
2) define all fields of the primary key as public variables in the class
3) override public int hashCode()
and public boolean equals (Object obj)
but when i deploy the beans in jboss it is giving
"The primary key class must override equals()" error
what could be the problem
Thanks in advance
Binny

Add a method boolean equals(Object o) see java.lang.Object. This is required for comparisons, also hashCode needed.

Composite Primary Key in Form

Hi, I have a table which maintains versions. This has a composite primary key - eg - Company_id + version_no. I tried creating a form based on a template with Primary key as Company_id and primary key column 2 as Version_no. When I try to run the form it gives an error, 'Invalid number' on the process in Rendering page. When i remove the second primary key the results are displayed correctly (however I have a problem when there are more than 1 versions - too many rows).
How do I create a form based on a template with a composite key.
How can I create a form which has more than 2 keys as part of a composite primary key.

This thread is old....but let me make some notice...
Oracle guys,
does all that mean that you encourige using simple PK which is based on sequence, regardless that involve unique index on columns that normaly represent PK, but in master detail wizard it is impossible to use composite keys?
Why I'm asking this?
Because many apps are translated to HTMLDB (Oracle based) directly with not too much problems. But if we have to change PK then many things are complicated...
This all come from a problem how to fill detail table PK where first coulmn represent master key field and second one is filled with user input-nothing can be automated.
In your demo I saw that for "orders-order items" you use "simple PK" technique, regardless order items could have PK made from (OrderId, Id)...
Please make some respond for this....
THX!

Null Field in Composite Primary Key

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