Introduction to PostgreSQL bigserial Data Type

bigserial data type is a data type in PostgreSQL database used for automatically generating unique identifiers. It is a special data type in PostgreSQL that is actually an 8-byte integer (i.e., bigint type), similar to serial type, but capable of storing larger values.

Here is detailed information about the bigserial data type.

Syntax

The bigserial data type can be defined using the following syntax when creating a table:

column_name bigserial

Use Cases

The bigserial data type is used when you need to generate a unique identifier for each row in a table. Typically, it is used as a replacement for manually maintaining identifiers, such as using auto-incrementing integers or globally unique identifiers (GUIDs).

Example

The following example shows how to use the bigserial data type in PostgreSQL.

Create a table named students with columns id, name, and age. The id column uses the bigserial data type:

CREATE TABLE students (
    id bigserial PRIMARY KEY,
    name varchar(50) NOT NULL,
    age int NOT NULL
);

In the above example, the id column is defined as a primary key using the PRIMARY KEY constraint. Since the bigserial type is auto-incrementing, you do not need to manually specify the id value when inserting new rows:

INSERT INTO students (name, age) VALUES ('Alice', 20);
INSERT INTO students (name, age) VALUES ('Bob', 22);
INSERT INTO students (name, age) VALUES ('Charlie', 21);

Query the students table:

SELECT * FROM students;

Result:

 id |  name   | age
----+---------+-----
  1 | Alice   |  20
  2 | Bob     |  22
  3 | Charlie |  21
(3 rows)

In the above example, you can see that the values of the id column are automatically incremented.

Conclusion

The bigserial data type is a special data type in PostgreSQL used for generating unique identifiers. It is a subtype of bigint type and can store larger values. With the bigserial data type, you can easily generate unique identifiers for each row in a table, avoiding the complexity and errors of manually maintaining identifiers.