What is the degree of a relation in a relational database?

Concept: A relation (table) in the relational model carries two distinct structural counts: its degree, the number of attributes (columns) fixed by the relation schema, and its cardinality, the number of tuples (rows) present in a given instance, a count that varies as rows are inserted or deleted.

Application: The question asks specifically for the degree of a relation. By definition, degree counts the attributes defined in the relation’s schema — for example, a relation Student(RollNo, Name, Class, Marks) has degree 4, regardless of how many student rows (tuples) it currently holds.

Contrast:

• Number of tuples is the relation’s cardinality, not its degree — this count changes with every insert or delete, whereas degree is fixed by the schema.

• Number of keys counts attribute subsets used for uniqueness (primary key, candidate keys) — a structural identifier property, not a count of attributes.

• Number of constraints counts integrity rules (domain, referential-integrity, etc.) imposed on the relation — unrelated to how many attributes it has.

Cross-check: Counting the columns of Student(RollNo, Name, Class, Marks) directly gives 4 — matching the definition of degree and confirming that a relation’s degree is the number of attributes it has, independent of any particular instance’s row count.