Basic Knowledge of Database

1. What is a database?

A database is a warehouse for storing data. This warehouse is organized and stored according to certain data results. We can manage the data in the database through a variety of methods provided by the database.

1. Types of databases
   There are three popular database models in the early days, namely Hierarchical Database, Network Database and Relational Database. In today’s Internet, the most commonly used database models are mainly two types, namely Relational Databases and Non-Relational Databases.

2. Introduction to Relational Database
   Network Databases and Hierarchical Databases lack data independence and abstraction levels. When users carry out storage, they need to declare the storage structure and relative path of the data. Relational Database can solve this problem more effectively.

Like Excel workbooks, Relational Databases also use two-dimensional tables composed of columns and rows to manage data, which is easy to understand. In addition, it uses SQL to perform actual operations on the data.

1. Introduction to Non-Relational Database With the rise of Internet technology, traditional relational databases have exposed many difficulties when dealing with large amounts of data. Therefore, a database product-NOSQL Database, which aims at large-scale data volume scenarios and aims at excellent performance and convenient application.

Non-Relational Databases are mainly based on the “non-relational entity model” database, also known as NoSQL database. The original intent of NOSQL is “Not only SQL”. Therefore, the emergence of NoSQL is not to completely deny relational databases, just as a A reasonable supplement to traditional relational databases.

Non-Relational Databases can also be subdivided into four small items:

1) Key-Value storage database;
2) Column-oriedted database;
3) Document-Oriented database;
4) Graph database.