extend schema
    @link(
        url: "https://specs.apollo.dev/federation/v2.3",
        import: ["@key", "@external", "@requires"]
     )

type Query {
  student(id: ID!): Student
  students: [Student]
}

type Student @key(fields: "id") {
  id: ID!
  name: String
  enrollments: [Enrollment]
}

type Enrollment @key(fields: "studentId courseId") {
  studentId: ID!
  courseId: ID!
  course: Course @provides(fields: "name")
  enrollmentDate: String
}

extend type Course @key(fields: "id") {
  id: ID! @external
  enrolledStudents: [Student] @requires(fields: "id")
}