Domain relational calculus

Domain Relational Calculus is a way of using math to figure out things from a database. Imagine you have a list of names, addresses, and phone numbers. You can use domain relational calculus to ask questions about the list. For example, you could ask "Which names belong to people who live in 'Washington'?" or "Which addresses have phone numbers that start with '555'?" Domain relational calculus is like a type of math that helps you learn things about the list.