What are constraints in SQL?
SQL Constraints are rules used to limit the type of data that can go into a table, to maintain the accuracy and integrity of the data inside the table.
What is a Database?
A database is an organized collection of data. A relational database, more restrictively, is a collection of schemas, tables, queries, reports, views, and other elements
What is a URL?
URL is the abbreviation of Uniform Resource Locator and is defined as the global address of documents and other resources on the World Wide Web.