Attribute Values, Data Domains, and Data Types
Understand how PostgreSQL implements relational theory concepts such as attribute values, data domains, and tuples. Learn how business constraints like timestamp validation enforce data consistency using the Gregorian calendar. Discover how PostgreSQL handles date-specific queries and data types with practical examples.
Relation
The definition for relation mentions attribute values that are part of data domains. A domain here is similar to the one we read about in mathematics—a set of values that are given a common name. There’s the data domain of natural numbers and the data domain of rational numbers in mathematics.
Tuple
In relational theory, we can compose basic data domains into a tuple. The definition for a tuple is as follows:
“The term originated as an abstraction of the sequence: single, double, triple, quadruple, ...