PostgreSQL AUTO INCREMENT (Automatic Increment)

AUTO INCREMENT (Automatic Increment) generates a unique number when a new record is inserted into a table.

PostgreSQL uses sequences to identify field auto-incrementing, with data types such as smallserial, serial, and bigserial. These attributes are similar to the AUTO_INCREMENT attribute supported by MySQL databases.

The statement to set up auto-increment in MySQL is as follows:

CREATE TABLE IF NOT EXISTS `tutorialpro_tbl`(
   `tutorialpro_id` INT UNSIGNED AUTO_INCREMENT,
   `tutorialpro_title` VARCHAR(100) NOT NULL,
   `tutorialpro_author` VARCHAR(40) NOT NULL,
   `submission_date` DATE,
   PRIMARY KEY ( `tutorialpro_id` )
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

MySQL uses the AUTO_INCREMENT attribute to identify field auto-incrementing.

PostgreSQL uses sequences to identify field auto-incrementing:

CREATE TABLE tutorialpro
(
    id serial NOT NULL,
    alttext text,
    imgurl text
)

SMALLSERIAL, SERIAL, and BIGSERIAL Ranges:

Syntax

The basic syntax for the SERIAL data type is as follows:

CREATE TABLE tablename (
   colname SERIAL
);

Example

Suppose we want to create a COMPANY table and create the following fields:

tutorialprodb=# CREATE TABLE COMPANY(
   ID  SERIAL PRIMARY KEY,
   NAME           TEXT      NOT NULL,
   AGE            INT       NOT NULL,
   ADDRESS        CHAR(50),
   SALARY         REAL
);

Now, insert several records into the table:

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 );

View the records in the COMPANY table as follows:

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