Composite Primary Key needs Unique ID column or no?

Hello Dears ,
I have a table that it's primary key is composite key of two columns , and there are like 5 info columns . You think I shall use the two columns as primary key of this table or create unique ID column .
Example :
Table Employees :
Table Departments :
The problem table is Department Managers :
Now I'll be adding employee id and department id in this table plus manager info etc..( info doesnt exist in employee table) , shall i use them as primary or create id column in this table ??
Thanks alot.

Hi
I would use employe_id and department_id to define the PK. I see no reason for adding a meaningless key in such a case.
HTH
Chris Antognini
Troubleshooting Oracle Performance, Apress 2008
http://top.antognini.ch

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>

Composite primary key on very large tables...

Hello
So I'm building a database where one of the tables will eventually have > 1 billion rows and was wondering about the primary key. The table will have 3 columns (sample_id, object_id, value) and so I was thinking instead of creating a surrogate key I would create a composite primary key on those 3 columns.... People will query either for sample_id = X or object_id = Y. I've created a composite index on object_id, sample_id and value and the query times have been fast < 2-3s per object_id. Although building that index takes some time (7-8 hrs) what would be the pros/cons to composite PK vs a unique index? I plan to do massive bulk uploads (50M records at a time) so I'll disable the constraints before loading.... These records will also be loaded in order so would a clustered table be appropriate?
thanks
steve

Hi,
As correctly said by steve,partition the table.
Create a unique index on single column and then even if ur query is not using that column which has index,use a HINT and make it to use the index.
If ur using joins on this table with other tables u can use use_hash hint which will improve performance.
Hope it helps.
Thanks

Can I add a new column to a composite primary key without dropping it?

Hi
I need to modify the composite primary key of a table so as to include an another additional column to it?
Can I do that without dropping the PRIMARY KEY constraint on the table?

user13410062 wrote:
Hi
I need to modify the composite primary key of a table so as to include an another additional column to it?
Can I do that without dropping the PRIMARY KEY constraint on the table?post results from ALTER TABLE command

Maximum number of column in Composite Primary Key

Hi
I have read that composite primary key can contain maximum of 32 columns (Oracle 9i).
However I am able to create a primary key on 33 columns. It fails to create primary key on 34 columns. Below are the queries.
DROP TABLE XYZ;
CREATE TABLE XYZ
( N1 NUMBER
,N2 NUMBER
,N3 NUMBER
,N4 NUMBER
,N5 NUMBER
,N6 NUMBER
,N7 NUMBER
,N8 NUMBER
,N9 NUMBER
,N10 NUMBER
,N11 NUMBER
,N12 NUMBER
,N13 NUMBER
,N14 NUMBER
,N15 NUMBER
,N16 NUMBER
,N17 NUMBER
,N18 NUMBER
,N19 NUMBER
,N20 NUMBER
,N21 NUMBER
,N22 NUMBER
,N23 NUMBER
,N24 NUMBER
,N25 NUMBER
,N26 NUMBER
,N27 NUMBER
,N28 NUMBER
,N29 NUMBER
,N30 NUMBER
,N31 NUMBER
,N32 NUMBER
,N33 NUMBER
,N34 NUMBER
,N35 NUMBER
,N36 NUMBER
,N37 NUMBER
,N38 NUMBER
,N39 NUMBER
,N40 NUMBER
,N41 NUMBER
,N42 NUMBER
,N43 NUMBER
,N44 NUMBER
,N45 NUMBER
,N46 NUMBER
,N47 NUMBER
,N48 NUMBER
,N49 NUMBER
,N50 NUMBER
ALTER TABLE XYZ ADD CONSTRAINT XYZ_PK PRIMARY KEY
( N1,N2,N3,N4,N5,N6,N7,N8,N9,N10,N11,N12,N13,N14
,N15,N16,N17,N18,N19,N20,N21,N22,N23,N24,N25,N26
,N27,N28,N29,N30,N31,N32,N33,N34);
ALTER TABLE XYZ ADD CONSTRAINT XYZ_PK PRIMARY KEY
( N1,N2,N3,N4,N5,N6,N7,N8,N9,N10,N11,N12,N13,N14
,N15,N16,N17,N18,N19,N20,N21,N22,N23,N24,N25,N26
,N27,N28,N29,N30,N31,N32,N33);
Can someone let me know the lmit of maximum no. of columns in Primary Key?
Regards
Arun

SQL> select * from v$version;
BANNER
Oracle9i Enterprise Edition Release 9.2.0.1.0 - Production
PL/SQL Release 9.2.0.1.0 - Production
CORE     9.2.0.1.0     Production
TNS for 32-bit Windows: Version 9.2.0.1.0 - Production
NLSRTL Version 9.2.0.1.0 - Production
SQL> ALTER TABLE XYZ ADD CONSTRAINT XYZ_PK PRIMARY KEY
2 ( N1,N2,N3,N4,N5,N6,N7,N8,N9,N10,N11,N12,N13,N14
3 ,N15,N16,N17,N18,N19,N20,N21,N22,N23,N24,N25,N26
4 ,N27,N28,N29,N30,N31,N32,N33);
Table altered.

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....

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.

SQL Statement for Composite Primary key

Hi,
I need a SQL statement for finding the Distinct values for combination of 2 Columns( Composite Primary key). I dont want to use Data Dictionary views.
Table A
c1 c2
1 1
1 2
2 3
Now for the above table combination of c1 and c2 is unique.
Please advice.
Cheers
Ramkannan.A

This?
PRAZY@solarc> with tableA as
2 (select 1 col1,2 col2 from dual
3 union all
4 select 1,1 from dual
5 union all
6 select 1,2 from dual
7 union all
8 select 2,3 from dual
9 union all
10 select 1,2 from dual
11 union all
12 select 2,3 from dual
13 )
14 select distinct col1, col2 from TableA
15 /
      COL1       COL2
         2          3
         1          2
         1          1Regards,
Prazy

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

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

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 in oe_order_headers_all table?

Hi all
What are columns involved in composite primary key in oe_order_headers_all table? how to identify that?
(Order_number, order_type, org_id) are the combination of composite primary key or anything else ?

select * From all_constraints where table_name = 'OE_ORDER_HEADERS_ALL'
SELECT AIC.* FROM ALL_INDEXES AI, ALL_IND_COLUMNS AIC
WHERE AI.TABLE_NAME='OE_ORDER_HEADERS_ALL'
AND AI.UNIQUENESS='UNIQUE'
AND AI.INDEX_NAME = AIC.INDEX_NAME
order by AI.INDEX_NAME
Hope this helps,
Sandeep Gandhi

Composite Primary Key

Hi,
I have few tables which had primary key on one column A, I made it composite primary key by adding one more column B at 2nd position. I made this change in all the tables. When I ran few SQLs to check the performance I found that explain plan shows full table scan on few tables which was not showing eariler (before composite PK). The SQL has outer join between these tables on column A (1st position in composite PK index). Is there anything I need to look into?
I'm using Oracle 10.2.0.5.0.
Thanks

Onkar Talekar wrote:
I guess you are talking about the same table in this thread: [url:https://forums.oracle.com/forums/thread.jspa?threadID=2372871&start=0&tstart=0]Primary Key modification
Yes. thats right.
If it is the same post, could you post current structure of the table plus what is recommended in the FAQ to post for performance issues?
Have you replaced your primary key from PARENT_ID to a composite primary key (PARENT_ID, PT_TIME)?
What was the reason for that?
Did you have any need to insert the same key (PARENT_ID) with different PT_TIME?
What is the benefit you expected creating this index?
What did you mean with "contention" that is happening on this primary key/index? Someone using the same primary key?
How is the PARENT_ID generated?
At a first look I did not see the need of replacing your primary key, as Tubby advised in your previous post. Adding a column to solve contention added additional trouble to you on performance side.
Regards.
Al.

Composite primary key as foreign key not working

i want have two tables
in one table i make a composite primary key
and in the other table i refer one of the column of the composite key from the above table as foreign key in this table but this didn't work.
eg:
create table temp1
( name char2(10),
ssn# number(10)
address varchar2(10)
constraint (cons_1)primary key(name,ssn#) );
create table temp2
( name1 char2(10) references temp1(name),
add varchar(20));
this didn't work....can't create temp2 table it's giving error

The following includes some corrections and some suggestions. Your original code had several problems: missing comma, invalid name, invalid data type, no unique key for the foreign key to reference. The following fixes all of those and adds some meaningful names for the constraints and formats it so that it is easier to read.
CREATE TABLE temp1
(name       VARCHAR2 (10),
   ssn#       NUMBER   (10),
   address    VARCHAR2 (10),
   CONSTRAINT temp1_name_ssn#_pk
              PRIMARY KEY (name, ssn#),
   CONSTRAINT temp1_name_uk
              UNIQUE (name))
Table created.
CREATE TABLE temp2
(name1      VARCHAR2 (10),
   address    VARCHAR2 (20),
   CONSTRAINT temp2_name1_fk
              FOREIGN KEY (name1)
              REFERENCES temp1 (name))
Table created.

Composite Primary Key needs Unique ID column or no?

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