Types of Relational calculus:
1. Tuple Relational Calculus (TRC)
T is the resulting tuples
P(T) is the condition used to fetch T.
OUTPUT: This query selects the tuples from the AUTHOR relation. It returns a tuple with 'name' from Author who has written an article on 'database'.
TRC (tuple relation calculus) can be quantified. In TRC, we can use Existential (∃) and Universal Quantifiers (∀).
Output: This query will yield the same result as the previous one.
2. Domain Relational Calculus (DRC)
a1, a2 are attributes
Output: This query will yield the article, page, and subject from the relational javatpoint, where the subject is a database.