Relational calculus

Relational calculus consists of two calculi, the tuple relational calculus and the domain relational calculus, that are part of the relational model for databases and provide a declarative way to specify database queries. This in contrast to the relational algebra, which is also part of the relational model but provides a more procedural way for specifying queries. Relational calculus consists of two calculi, the tuple relational calculus and the domain relational calculus, that are part of the relational model for databases and provide a declarative way to specify database queries. This in contrast to the relational algebra, which is also part of the relational model but provides a more procedural way for specifying queries. The relational algebra might suggest these steps to retrieve the phone numbers and names of book stores that supply Some Sample Book: