сделал DDL для пет проекта

mnoskov/postgresql/Пет-проект: Онлайн-курсы/1. Создание таблиц и связей/DDL_create_tables_for_pet_project.sql

@@ -0,0 +1,45 @@
+--DROP TABLE IF EXISTS users;
+CREATE TABLE users (
+	id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+	name varchar(100) NOT NULL,
+	age SMALLINT,
+	email varchar(100),
+	registration_date timestamptz NOT NULL
+);
+
+--DROP TABLE IF EXISTS courses;
+CREATE TABLE courses (
+	id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+	title varchar(150) NOT NULL,
+	category varchar(50),
+	created_at timestamptz NOT NULL
+);
+
+--DROP TABLE IF EXISTS lessons;
+CREATE TABLE lessons (
+	id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+	course_id bigint NOT NULL,
+	title varchar(150) NOT NULL,
+	duration_min SMALLINT NOT NULL,
+	FOREIGN KEY (course_id) REFERENCES courses(id)
+);
+
+--DROP TABLE IF EXISTS enrollments;
+CREATE TABLE enrollments (
+	id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+	user_id bigint NOT NULL,
+	course_id bigint NOT NULL,
+	enrolled_at timestamptz NOT NULL,
+	FOREIGN KEY (user_id) REFERENCES users(id),
+	FOREIGN KEY (course_id) REFERENCES courses(id)
+);
+
+--DROP TABLE IF EXISTS lesson_views;
+CREATE TABLE lesson_views (
+	id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+	user_id bigint NOT NULL,
+	lesson_id bigint NOT NULL,
+	viewed_at timestamptz NOT NULL,
+	FOREIGN KEY (user_id) REFERENCES users(id),
+	FOREIGN KEY (lesson_id) REFERENCES lessons(id)
+);