Why doesn't my primary key work?

Question

PostgreSQL

I don’t understand a little why the primary key doesn’t work for me and it goes constantly as a null value.
Here is a screenshot

It seems that it should increase?

Answer 1

PostgreSQL has smallserial, serial and bigserial data types. They are for creating unique identity columns. This is analogous to the AUTO_INCREMENT property found in some other databases.
You are using BIGINT type, replace with BIGSERIAL.
Simple example:

CREATE TABLE books (
  id              SERIAL PRIMARY KEY,
  title           VARCHAR(100) NOT NULL,
  primary_author  VARCHAR(100) NULL
);