Nodalite online ERD and SQL editor

-- Nodalite:dialect=postgresql
-- 1. Each student has a unique id and email.
create table students (
  id bigint generated always as identity primary key,
  name varchar(100) not null,
  email varchar(255) not null unique,
  created_at timestamp not null default current_timestamp
);

-- 2. Courses can exist before any student enrolls.
create table courses (
  id bigint generated always as identity primary key,
  title varchar(150) not null,
  description text
);

-- 3. Enrollments connect students and courses with foreign keys.
create table enrollments (
  id bigint generated always as identity primary key,
  student_id bigint not null references students(id) on delete cascade,
  course_id bigint not null references courses(id) on delete cascade,
  enrolled_at timestamp not null default current_timestamp,
  unique (student_id, course_id)
);

-- Try it: add a status column to enrollments and watch the ERD update.