diff --git a/etc/databases/mooc.sql b/etc/databases/mooc.sql
index 999103fe6..1a094f827 100644
--- a/etc/databases/mooc.sql
+++ b/etc/databases/mooc.sql
@@ -5,11 +5,11 @@
 -- Generic tables
 
 CREATE TABLE mutations (
-	id bigint AUTO_INCREMENT PRIMARY KEY,
+	id BIGINT AUTO_INCREMENT PRIMARY KEY,
 	table_name VARCHAR(255) NOT NULL,
-	operation enum ('INSERT', 'UPDATE', 'DELETE') NOT NULL,
-	old_value json NULL,
-	new_value json NULL,
+	operation ENUM ('INSERT', 'UPDATE', 'DELETE') NOT NULL,
+	old_value JSON NULL,
+	new_value JSON NULL,
 	mutation_timestamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP
 ) ENGINE = InnoDB
   DEFAULT CHARSET = utf8mb4
@@ -19,7 +19,7 @@ CREATE TABLE domain_events (
 	id CHAR(36) NOT NULL,
 	aggregate_id CHAR(36) NOT NULL,
 	name VARCHAR(255) NOT NULL,
-	body json NOT NULL,
+	body JSON NOT NULL,
 	occurred_on TIMESTAMP NOT NULL,
 	PRIMARY KEY (id)
 ) ENGINE = InnoDB
@@ -43,7 +43,7 @@ CREATE TRIGGER after_courses_insert
 	FOR EACH ROW
 BEGIN
 	INSERT INTO mutations (table_name, operation, new_value, mutation_timestamp)
-	VALUES ('courses', 'INSERT', json_object('id', new.id, 'name', new.name, 'duration', new.duration), now());
+	VALUES ('courses', 'INSERT', JSON_OBJECT('id', new.id, 'name', new.name, 'duration', new.duration), NOW());
 END;
 
 CREATE TRIGGER after_courses_update
@@ -54,9 +54,9 @@ BEGIN
 	INSERT INTO mutations (table_name, operation, old_value, new_value, mutation_timestamp)
 	VALUES ('courses',
 			'UPDATE',
-			json_object('id', old.id, 'name', old.name, 'duration', old.duration),
-			json_object('id', new.id, 'name', new.name, 'duration', new.duration),
-			now());
+			JSON_OBJECT('id', old.id, 'name', old.name, 'duration', old.duration),
+			JSON_OBJECT('id', new.id, 'name', new.name, 'duration', new.duration),
+			NOW());
 END;
 
 CREATE TRIGGER after_courses_delete
@@ -65,47 +65,51 @@ CREATE TRIGGER after_courses_delete
 	FOR EACH ROW
 BEGIN
 	INSERT INTO mutations (table_name, operation, old_value, mutation_timestamp)
-	VALUES ('courses', 'DELETE', json_object('id', old.id, 'name', old.name, 'duration', old.duration), now());
+	VALUES ('courses', 'DELETE', JSON_OBJECT('id', old.id, 'name', old.name, 'duration', old.duration), NOW());
 END;
 
 CREATE TABLE courses_counter (
 	id CHAR(36) NOT NULL,
 	total INT NOT NULL,
-	existing_courses json NOT NULL,
+	existing_courses JSON NOT NULL,
 	PRIMARY KEY (id)
 ) ENGINE = InnoDB
   DEFAULT CHARSET = utf8mb4
   COLLATE = utf8mb4_unicode_ci;
 
-INSERT INTO courses_counter
+INSERT INTO courses_counter (id, total, existing_courses)
 VALUES ("cdf26d7d-3deb-4e8c-9f73-4ac085a8d6f3", 0, "[]");
 
 CREATE TABLE steps (
 	id CHAR(36) NOT NULL,
 	title VARCHAR(255) NOT NULL,
 	duration INT NOT NULL,
-	type VARCHAR(255) NOT NULL
+	type VARCHAR(255) NOT NULL,
+	PRIMARY KEY (id)
 ) ENGINE = InnoDB
   DEFAULT CHARSET = utf8mb4
   COLLATE = utf8mb4_unicode_ci;
 
 CREATE TABLE steps_video (
 	id CHAR(36) NOT NULL,
-	url VARCHAR(255) NOT NULL
+	url VARCHAR(255) NOT NULL,
+	FOREIGN KEY (id) REFERENCES steps(id) ON DELETE CASCADE
 ) ENGINE = InnoDB
   DEFAULT CHARSET = utf8mb4
   COLLATE = utf8mb4_unicode_ci;
 
 CREATE TABLE steps_exercise (
 	id CHAR(36) NOT NULL,
-	content VARCHAR(255) NOT NULL
+	content VARCHAR(255) NOT NULL,
+	FOREIGN KEY (id) REFERENCES steps(id) ON DELETE CASCADE
 ) ENGINE = InnoDB
   DEFAULT CHARSET = utf8mb4
   COLLATE = utf8mb4_unicode_ci;
 
 CREATE TABLE steps_quiz (
 	id CHAR(36) NOT NULL,
-	questions TEXT NOT NULL
+	questions TEXT NOT NULL,
+	FOREIGN KEY (id) REFERENCES steps(id) ON DELETE CASCADE
 ) ENGINE = InnoDB
   DEFAULT CHARSET = utf8mb4
   COLLATE = utf8mb4_unicode_ci;