I think it would help if you were to describe what real life situation is being modelled here, and what tables, and relationships between them, make up the model. Your references to 'course' and 'score' suggests to me that you are modelling something
like students' (or similar) performances in courses. If so, a student's score would be an attribute of the many-to-many relationship type between students and courses, each of which is modelled by a table, so would be modelled by a table which resolves
the many-to-many relationship type into two one-to-many relationship types like this:
StudentCourses
….StudentID (FK)
….CourseID (FK)
….Score
The table might have other columns representing other attributes of the relationship type. The primary key, if a student takes a course only once, would be a composite one made up of the two foreign keys.
With a model like this appropriate interfaces would be a bound students form, or a courses form, in single form view, with, in either case, a bound StudentCourses subform, in continuous forms view. In the parent form you would then simply navigate to
a course or student, and enter the score into the relevant row in the subform.
You might well be modelling something totally different , of course, but until you have provided us with a more detailed description of what you are aiming at, we are not in a position to offer detailed advice.
Ken Sheridan, Stafford, England