Beta Phase: Square45 is currently in beta testing. Expect some features or content to be incomplete or missing.
45

Relation Schema

The formal description of a relation, specifying its attributes and their data types within the relational model.
📜

The statement of the theorem

Define a relation schema RR as a tuple Schema(R)=(A1,A2,...,An)\text{Schema}(R) = (A_1, A_2, \text{...}, A_n), where AiA_i is the name of the ii-th attribute, and Dom(Ai)\text{Dom}(A_i) is the specified domain (set of allowed values) for that attribute. The set of all possible tuples for RR is the Cartesian product of the domains: Tuples(R) = Dom(A1)× Dom(A2)× ...× Dom(An)\text{Tuples}(R) \text{ } = \text{ } \text{Dom}(A_1) \times \text{ } \text{Dom}(A_2) \times \text{ } \text{...} \times \text{ } \text{Dom}(A_n).