What are attributes and entities in database system management?

Answer 1

Entities are the things you're keeping track of. In an video rental database, you keep track of customers, invoices, titles, copies, etc. These are represented in tables where the rows are individual instances of a customer or title. The columns are the attributes, the things that tell us about the instance in the row. The customer's name, address, city, balance, etc. are attributes that help identify the customer. An invoice's attributes might be price, number, date, paid/unpaid, etc. Databases link entities/tables so that a customer, described by his attributes, can be associated with his invoices, describe by his attributes and selected by the invoices 'unpaid' column. "Here's your bills for the last month, Mr. Smith."