Domain Relational Calculus
Learn how to write and interpret Domain Relational Calculus queries to retrieve data using declarative logic-based notation.
We'll cover the following...
Imagine we have a very specific query for our OnlineStore: Show the names of all products that cost less than $20 and are in the ‘Books’ category. We are not concerned with the steps required to locate this information; rather, we are focused on obtaining the result that matches the description. This approach—describing what we want instead of detailing how to retrieve it—forms the foundation of declarative query languages. In this lesson, we will explore Domain Relational Calculus (DRC), a formal language that exemplifies this principle.
By the end of this lesson, we’ll be able to:
Understand the core concepts of DRC.
Recognize the syntax and structure of a DRC query.
Differentiate DRC from its counterpart, Tuple Relational Calculus.
Formulate queries to retrieve specific data using DRC notation.
Domain relational calculus
DRC forms the conceptual foundation of practical query languages such as Structured Query Language (SQL).
Understanding DRC enhances our appreciation of the declarative power inherent in modern database systems. Rather than writing complex, step-by-step procedures, users simply define the properties of the desired data, and the Database Management System (DBMS) performs the necessary operations to retrieve it.
DRC is a nonprocedural, formal query ...