How to have a unique value for each record??

Question

could any 1 help me out in this...
I want to have a column name 'Order No' which should be unique.
How to generate a unique value for each record.??

Answer 1

could any 1 help me out in this...
I want to have a column name 'Order No' which should be unique.
How to generate a unique value for each record.?? If you are using SQL PLUS to create the table try something like
this:
CREATE TABLE ORDER_TEST (
ORD_NO NUMBER (8) NOT NULL PRIMARY KEY,
ORDERDATE DATE,
CUSTID NUMBER (8) NOT NULL,
SHIPDATE DATE,
TOTAL NUMBER (8,2) CONSTRAINT TOTAL_ZERO CHECK
(TOTAL >= 0),
CONSTRAINT ORD_FOREIGN_KEY FOREIGN KEY (CUSTID) REFERENCES
CUSTOMER (CUSTID),
CONSTRAINT ORD_UNIQUE UNIQUE (ORD_NO)
-- or a simpler table example
DROP TABLE ORDER_TEST;
CREATE TABLE ORDER_TEST (
ORD_NO NUMBER (8),
ORDERDATE DATE,
CUSTID NUMBER (8) NOT NULL,
SHIPDATE DATE,
TOTAL NUMBER (8,2) CONSTRAINT TOTAL_ZERO CHECK
(TOTAL >= 0),
CONSTRAINT ORD_UNIQUE UNIQUE (ORD_NO)
note: ORD_NO can also be a primary key
If you are doing the INSERT during runtime from a form first
create a sequence in SQL PLUS to handle the ORD_NO value:
Create SEQUENCE ORDERNO_UNIQUEVAL_sqnc
START WITH 000001
NOMAXVALUE
NOCACHE;
and reference it as the ORD_NO parameter in your INSERT
statement:
ORDERNO_UNIQUEVAL_sqnc.NEXTVAL
note: to maintain data integrity you must use the sequence
everytime you insert a new order to table. To start a new
sequence drop the sequence and re-create it with whatever "START
WITH" value you want.
Hope this helps
Kevin