Introduction to Database Systems

What is a database system?

Database system = Database (db) + Database Management System (DBMS) + database application (Application (DBA ))

Database: A collection of logically related shareable data and data descriptions designed to meet the information needs of an organization, with the purpose of saving data.

Database management system: the software that controls and manages the access to the database. The role is to contact the database and the data application.

Database application: An application that interacts with a database through a DBMS, interacting with the user.

Why should I have a database system?

Before the database system, a file-based system is used. A file-based system is a collection of applications that provide services to end users, and each program defines and manages its own data.

In general, we can retrieve the data through the folder, index classification, but when the cross-reference (cross-reference) or retrieve the information in the file, the file-based system is not good. In addition, file-based systems also have data dispersion, redundancy, data interdependence, and file formats that depend on applications (file embedding programs). As a result, a database was subsequently presented. The database is a collection of logically related data that minimizes copies of the data and is decoupled from the program to solve the problem of file-based systems.

Database composition?

Database = data structure + constraints + data operations

relational database = two-dimensional table (data structure) + entities, references, business constraints (constraints) + relational operations (data operations)

Introduction to Database Systems