added create_tables and inser_data files

skonev/postgresql/create_tables.sql

@@ -0,0 +1,45 @@
+BEGIN;
+
+CREATE TABLE SKONEV.users(
+	id INT PRIMARY KEY, 
+	name VARCHAR(100), 
+	age INT, 
+	email VARCHAR(255) UNIQUE, 
+	registration_date DATE NOT NULL
+	);
+
+CREATE TABLE SKONEV.courses(
+	id INT PRIMARY KEY,
+	title TEXT NOT NULL,
+	category VARCHAR(255) CHECK (category IN ('data', 'programming', 'business')),
+	created_at DATE NOT NULL
+	);
+
+CREATE TABLE SKONEV.lessons(
+	id INT PRIMARY KEY, 
+	course_id INT NOT NULL,
+	FOREIGN KEY (course_id) REFERENCES courses(id), 
+	title TEXT NOT NULL, 
+	duration_min INT NOT NULL
+	);
+
+
+CREATE TABLE SKONEV.enrollments(
+	id INT PRIMARY KEY, 
+	user_id INT NOT NULL,
+	FOREIGN KEY (user_id) REFERENCES users(id), 
+	course_id INT NOT NULL,
+	FOREIGN KEY (course_id) REFERENCES courses(id), 
+	enrolled_at DATE NOT NULL
+	);
+
+CREATE TABLE SKONEV.lesson_views(
+	id INT PRIMARY KEY, 
+	user_id INT NOT NULL,
+	FOREIGN KEY (user_id) REFERENCES users(id), 
+	lesson_id INT NOT NULL,
+	FOREIGN KEY (lesson_id) REFERENCES lessons(id), 
+	viewed_at TIMESTAMP NOT NULL
+	);
+
+COMMIT;

skonev/postgresql/insert_data.sql

@@ -0,0 +1,42 @@
+BEGIN;
+
+INSERT INTO SKONEV.users (id, name, age, email, registration_date)
+VALUES
+(1, 'Alice', 25, 'alice@mail.com', '2023-01-10'),
+(2, 'Bob', 30, 'bob@gmail.com', '2023-02-05'),
+(3, 'Charlie', 22, 'charlie@mail.com', '2023-02-20'),
+(4, 'Diana', 28, 'diana@mail.com', '2023-03-01'),
+(5, 'Ethan', 35, 'ethan@gmail.com', '2023-03-10');
+
+INSERT INTO SKONEV.courses (id, title, category, created_at)
+VALUES
+(1, 'SQL для начинающих', 'data', '2023-01-01'),
+(2, 'Python для анализа данных', 'programming', '2023-01-15'),
+(3, 'BI с нуля', 'business', '2023-03-01');
+
+INSERT INTO SKONEV.lessons (id, course_id, title, duration_min)
+VALUES
+(1, 1, 'SELECT и FROM', 10),
+(2, 1, 'JOIN', 15),
+(3, 2, 'Pandas', 20),
+(4, 3, 'Основы BI', 12),
+(5, 3, 'Метрики и дашборды', 18);
+
+INSERT INTO SKONEV.enrollments (id, user_id, course_id, enrolled_at)
+VALUES
+(1, 1, 1, '2023-01-15'),
+(2, 1, 2, '2023-02-01'),
+(3, 2, 1, '2023-01-20'),
+(4, 3, 2, '2023-03-05'),
+(5, 4, 3, '2023-04-01');
+
+INSERT INTO SKONEV.lesson_views (id, user_id, lesson_id, viewed_at)
+VALUES
+(1, 1, 1, '2023-01-16 10:00:00'),
+(2, 1, 2, '2023-01-16 10:15:00'),
+(3, 2, 1, '2023-01-21 09:00:00'),
+(4, 3, 3, '2023-03-06 12:00:00'),
+(5, 4, 4, '2023-04-02 10:00:00'),
+(6, 4, 5, '2023-04-03 10:00:00');
+
+COMMIT;