Index: .idea/sqldialects.xml
===================================================================
--- .idea/sqldialects.xml	(revision 4299936e23147060b2027ace52e960d67b3dd20b)
+++ .idea/sqldialects.xml	(revision c4c2edf5cb930fa6aecb7132493e92bf47a378ee)
@@ -2,4 +2,5 @@
 <project version="4">
   <component name="SqlDialectMappings">
+    <file url="file://$PROJECT_DIR$/music/constrains/constrains.sql" dialect="PostgreSQL" />
     <file url="file://$PROJECT_DIR$/music/procedures/insert_track_with_price.sql" dialect="PostgreSQL" />
     <file url="file://$PROJECT_DIR$/music/triggers/customer_deletion.sql" dialect="PostgreSQL" />
Index: music/constrains/constrains.sql
===================================================================
--- music/constrains/constrains.sql	(revision c4c2edf5cb930fa6aecb7132493e92bf47a378ee)
+++ music/constrains/constrains.sql	(revision c4c2edf5cb930fa6aecb7132493e92bf47a378ee)
@@ -0,0 +1,11 @@
+-- Default Media Type Constrain
+ALTER TABLE track
+ALTER COLUMN media_type_id SET DEFAULT 1;
+
+ALTER TABLE track
+DROP CONSTRAINT IF EXISTS track_media_type_id_fkey;
+
+ALTER TABLE track
+ADD CONSTRAINT track_media_type_id_fkey
+FOREIGN KEY (media_type_id) REFERENCES media_type(media_type_id)
+ON DELETE SET DEFAULT;
Index: music/triggers/media_type_deletion.sql
===================================================================
--- music/triggers/media_type_deletion.sql	(revision 4299936e23147060b2027ace52e960d67b3dd20b)
+++ music/triggers/media_type_deletion.sql	(revision c4c2edf5cb930fa6aecb7132493e92bf47a378ee)
@@ -1,20 +1,14 @@
-CREATE OR REPLACE FUNCTION media_type_deletion()
+CREATE OR REPLACE FUNCTION prevent_deletion_of_default_media_type()
 RETURNS TRIGGER AS $$
 BEGIN
     IF OLD.media_type_id = 1 THEN
-        RAISE EXCEPTION 'Cannot delete default media type (MPEG audio file with id = 1).';
+        RAISE EXCEPTION 'Cannot delete default media type (id = 1)';
     END IF;
-
-    UPDATE track
-    SET media_type_id = 1
-    WHERE media_type_id = OLD.media_type_id;
-
     RETURN OLD;
 END;
 $$ LANGUAGE plpgsql;
 
-
-CREATE TRIGGER trg_media_type_deletion
+CREATE TRIGGER trg_prevent_deletion_of_default_media_type
 BEFORE DELETE ON media_type
 FOR EACH ROW
-EXECUTE FUNCTION media_type_deletion();
+EXECUTE FUNCTION prevent_deletion_of_default_media_type();