Database System introduction, database Introduction

Database System introduction, database Introduction
What is a database system?

DataBase System = Database (DB) + Database Management System (DBMS) + DataBase Application (DBA ))

Database: a set of logically related data that can be shared and data descriptions designed to meet the information requirements of an organization. It stores data.

Database Management System: software used to control and manage databases. The role is to contact the database and data applications.

Database applications: applications that interact with databases through DBMS.

 

Why do we need a database system?

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

In general, we can retrieve data through folders and index categories. However, when cross-reference or file information is retrieved, file-based systems cannot be used. In addition, file-based systems also have data dispersion, redundancy, mutual dependency between data, and file formats dependent on applications (File embedding programs. As a result, the database appeared later. The database aggregates logical-related data to minimize data copies and separate the data from the program, thus solving the file-based system problems.

Database structure?

Database = Data Structure + constraints + Data Operations

Relational Database = two tables (Data Structure) + entity, reference, business constraints (constraints) + relational operations (Data Operations)