Learning JavaScript Data Structures and Algorithms - Third Edition

Set operations

Set is one of the most basic concepts in mathematics and it is very important in computer science as well. One of the main applications in computer science is in databases, which are the roots of most applications. Sets are used in query design and processing. When we create a query to retrieve a set of data in a relational database (Oracle, Microsoft SQL Server, MySQL, and so on), we design the query using set notation and the database will also return a set of data. When we create an SQL query, we can specify whether we want to retrieve all the data from a table or only a subset. We can also retrieve data that is common to two tables, data that exists only in one table (and not in the other table), or data that exists in ...