Database introduction

database

  A database is a warehouse for storing and managing data , Data is stored in a certain format , Users can add data to the database 、 modify 、 Delete 、 Query and so on .

Types of databases

 Relational database ： A relational model is used to organize the database of data , Simply speaking , A relational model is a two-dimensional table model , like Excel The form in the file , Emphasize the use of tables to store data . Such as ：Oracle、Microsoft SQL Server、MySQL、SQLit etc. .
 Non relational database ： Also known as NoSQL（Not Only SQL ), It means more than SQL, Yes NoSQL  The most common definition is “ Uncorrelated ”, emphasize  Key-Value  How to store data . Such as ：MongoDB、Redis etc. .

The role of database

 The function of database is to store and manage data , such as :  The product list data we browsed on Jingdong website , These data will be stored in the database .

The characteristics of database

Persistent storage
Read and write very fast
Ensure the validity of data