diff --git a/mnoskov/greenplum/Пет проект: DWH/Step_3_core_layer.sql b/mnoskov/greenplum/Пет проект: DWH/Step_3_core_layer.sql
index c21d4fa..c2b6c59 100644
--- a/mnoskov/greenplum/Пет проект: DWH/Step_3_core_layer.sql	
+++ b/mnoskov/greenplum/Пет проект: DWH/Step_3_core_layer.sql	
@@ -5,23 +5,23 @@ CREATE TABLE core.dim_user (
 	user_id int PRIMARY KEY,
 	name text,
 	age int,
-	email text,
-	registration_date date
+	email text NOT NULL,
+	registration_date date NOT NULL
 ) DISTRIBUTED BY (user_id);
 
 --DROP TABLE IF EXISTS core.dim_course;
 CREATE TABLE core.dim_course (
 	course_id int PRIMARY KEY,
-	title text,
+	title text NOT NULL,
 	category text
 ) DISTRIBUTED BY (course_id);
 
 --DROP TABLE IF EXISTS core.dim_lesson;
 CREATE TABLE core.dim_lesson (
 	lesson_id int PRIMARY KEY,
-	title text,
+	title text NOT NULL,
 	duration_min int,
-	course_id int REFERENCES core.dim_course(course_id)
+	course_id int NOT NULL REFERENCES core.dim_course(course_id)
 ) DISTRIBUTED BY (lesson_id);
 
 --DROP TABLE IF EXISTS core.dim_date;
@@ -37,17 +37,17 @@ CREATE TABLE core.dim_date (
 -- 5
 --DROP TABLE IF EXISTS core.fact_lesson_views;
 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
+	user_id int NOT NULL REFERENCES core.dim_user(user_id),
+	lesson_id int NOT NULL REFERENCES core.dim_lesson(lesson_id),
+	course_id int NOT NULL REFERENCES core.dim_course(course_id),
+	viewed_at timestamp NOT NULL
 ) DISTRIBUTED BY (user_id);
 
 --DROP TABLE IF EXISTS core.enrollments;
 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
+	user_id int NOT NULL REFERENCES core.dim_user(user_id),
+	course_id int NOT NULL REFERENCES core.dim_course(course_id),
+	enrolled_at timestamp NOT NULL
 ) DISTRIBUTED BY (user_id);
 
 
@@ -101,7 +101,7 @@ SELECT
 FROM
 	raw.lesson_views lv
 JOIN
-	raw.lessons l ON lv.lesson_id = l.id
+	raw.lessons l ON lv.lesson_id = l.id;
 
 INSERT INTO core.enrollments (user_id, course_id, enrolled_at)
 SELECT