Represented as:
Rel_name(Attr_1:D_1,…,Attr_n:D_n
where:
- Rel_name: relation identifier
- Attr_i: attribute name
- D_1: basic domain.
- n: degree of relation.
- Rel_name also called n-ary tuples.
- Relation schema is also called intension and is time-invariant.
- Instances of a relation at some point in time are called the relation's extension. The relation extension is dynamic.






