Ask for help in the relations between the table

My brothers of the best forum I've set work schedules in accordance with the attached image with the file, please



- To assist in the work of relations such as what is in the attached image



- Tables are correct as it is in the picture.



- There's Data_Items_in_tests table in front of each of test_id field and test_data_item_id PF mark what is the brand.



- Please clarify the relationship between the tables Test_definitions, Data_Items_in_tests, Test_Data_Items, Test_Results because I did not understand what is the PF who in Data_Items_in_tests table



Please my brothers Add suggestions to correct relations and tabulator

Attached Files

البرنامج.zip (50.5 KB)

Ask for help in the relations between the table