PostgreSQL has the information types smallserial, sequential and bigserial; these are false sorts, yet simply a notational comfort for making special identifier segments. These are like AUTO_INCREMENT property upheld by some different information bases.
On the off chance that you wish a sequential segment to have a remarkable limitation or be an essential key, it should now be indicated, much the same as some other information type.
The sort name sequential makes a number segments. The sort name bigserial makes a bigint section. bigserial ought to be utilized on the off chance that you foresee the utilization of in excess of 231 identifiers over the lifetime of the table. The sort name smallserial makes a smallint section.
Syntax
The essential use of SERIAL dataype is as per the following −
CREATE TABLE tablename (
colname SERIAL
);
Example
Consider the COMPANY table to be made as follows −
testdb=# CREATE TABLE COMPANY(
ID SERIAL PRIMARY KEY,
NAME TEXT NOT NULL,
AGE INT NOT NULL,
ADDRESS CHAR(50),
SALARY REAL
);
Presently, embed the accompanying records into table COMPANY −
INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)
VALUES ( 'Paul', 32, 'California', 20000.00 );
INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)
VALUES ('Allen', 25, 'Texas', 15000.00 );
INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)
VALUES ('Teddy', 23, 'Norway', 20000.00 );
INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)
VALUES ( 'Mark', 25, 'Rich-Mond ', 65000.00 );
INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)
VALUES ( 'David', 27, 'Texas', 85000.00 );
INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)
VALUES ( 'Kim', 22, 'South-Hall', 45000.00 );
INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)
VALUES ( 'James', 24, 'Houston', 10000.00 );
This will embed seven tuples into the table COMPANY a lot will have the accompanying records −
id | name | age | address | salary
----+-------+-----+------------+--------
1 | Paul | 32 | California | 20000
2 | Allen | 25 | Texas | 15000
3 | Teddy | 23 | Norway | 20000
4 | Mark | 25 | Rich-Mond | 65000
5 | David | 27 | Texas | 85000
6 | Kim | 22 | South-Hall | 45000
7 | James | 24 | Houston | 10000