Add Primary Key & Not Null Constraints

SQL

Technical Specification

Write a CREATE TABLE statement for users with id primary key, email NOT NULL and UNIQUE, created_at NOT NULL.

Input/Output Samples

Input:users

Output:table with strong constraints

Optimal Logic Path

CREATE TABLE users (
  id          SERIAL PRIMARY KEY,
  name        VARCHAR(100),
  email       VARCHAR(150) NOT NULL UNIQUE,
  is_active   BOOLEAN DEFAULT TRUE,
  created_at  TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

Architectural Deep-Dive

Constraints at DB level ensure we never accidentally insert rows without critical fields or with duplicate emails.