-- Измерение пользователей
	CREATE TABLE core.dim_user (
	    user_id INT PRIMARY KEY,
	    name TEXT,
	    age INT,
	    email TEXT,
	    registration_date DATE
	)
	distributed by (user_id);
	
	-- Измерение курсов
	CREATE TABLE core.dim_course (
	    course_id INT PRIMARY KEY,
	    title TEXT,
	    category TEXT
	)
	distributed by (course_id);
	
	-- Измерение уроков
	CREATE TABLE core.dim_lesson (
	    lesson_id INT PRIMARY KEY,
	    title TEXT,
	    duration_min INT,
	    course_id INT REFERENCES core.dim_course(course_id)
	)
	distributed by (lesson_id);
	
	-- Опционально: измерение времени
	CREATE TABLE core.dim_date (
	    date DATE PRIMARY KEY,
	    year INT,
	    month INT,
	    day INT,
	    weekday TEXT
	)
	distributed replicated;
	
	-- Таблицы фактов:
	CREATE TABLE core.fact_lesson_views (
	    user_id INT REFERENCES core.dim_user(user_id),
	    lesson_id INT REFERENCES core.dim_lesson(lesson_id),
	    course_id INT REFERENCES core.dim_course(course_id),
	    viewed_at TIMESTAMP
	)
	distributed by (course_id);
	
	CREATE TABLE core.enrollments (
	    user_id INT REFERENCES core.dim_user(user_id),
	    course_id INT REFERENCES core.dim_course(course_id),
	    enrolled_at TIMESTAMP
	)
	distributed by (course_id);
	
	--ETL переброс данных из raw в core
	INSERT INTO core.dim_user (user_id, name, age, email, registration_date)
	SELECT DISTINCT
	    id::INT,
	    name::TEXT,
	    age::INT,
	    email::TEXT,
	    registration_date::DATE
	FROM raw.users;
	
	INSERT INTO core.dim_course (course_id, title, category)
	SELECT DISTINCT
	    id::INT,
	    title::TEXT,
	    category::TEXT
	FROM raw.courses;
	
	INSERT INTO core.dim_lesson (lesson_id, title, duration_min, course_id)
	SELECT DISTINCT
	    id::INT,
	    title::TEXT,
	    duration_min::INT,
	    course_id::INT
	FROM raw.lessons;
	
	-- Заполнение таблицы фактов
	insert into core.fact_lesson_views (user_id, lesson_id, course_id, viewed_at)
	select
		lw.user_id,
		lw.lesson_id,
		l.course_id,
		lw.viewed_at
	from raw.lessons_views lw
	join raw.lessons l on lw.lesson_id = l.id;
	
	insert into core.enrollments (user_id, course_id, enrolled_at)
	select
		user_id,
		course_id,
		enrolled_at
	from raw.enrollments;