sql server - How to solve cyclic relationship in SQL? -

i have table students , instructors , courses.

1. relationship between instructor , course many many (as instructor can teach many course , course can tough many instructors ) create instructorcourse table break many many
2. relationship between student , course many many (as student can register in many courses , course have many students) create studentcourse table break many many
3. relationship between student , instructor 1 many l have problem in cyclic relationship

you can create cross-relation tables mean can create studentcourses table example studentid & courseid fields (as composite primary key if required)