Little cuties, the knowledge we are going to learn next is database-related knowledge. Starting from this post, we will guide you from getting started to proficiency from 0 basics. Come on~
1 Introduction
1.1 Why study database?
Then we must first figure out the first question: Why learn the database?
Reason 1: The various web pages, applications, software systems, etc. that we browse or use now involve a lot of data.
For example: if you want to scan Douyin for a while, a lot of data will be generated, such as your account information, browsing information, likes, comments, forwarding, favorites, etc., and these data need to be saved and managed to facilitate programmers further processing of these data.
Reason 2: Our current study must be for subsequent employment or technical improvement needs. You may wish to click on the specific needs of the recruitment website. You can find that no matter whether you are a junior, intermediate or senior programmer, you need to be proficient in database technology. , so this is also a very important stepping stone for us. So we need to be proficient in the knowledge of databases, and I will post a post about database interview questions for you later.
1.2 What is a database? how to learn
In ancient times, if grain needed to be stored, it was stored in a granary, so a "granary" is a warehouse for storing grain.
The database, as the name suggests, is a "warehouse" for storing data, so that we can better store and manage data.
Before learning database-related knowledge, you first need to install a database before you can operate the database.
We operate the database through SQL, such as adding, querying, updating and deleting data.
After mastering the SQL language, we can meet the entry-level requirements of the database, that is, we can complete most of the business development work in actual development.
In the future, we will go further into the knowledge of database transactions, storage engines, indexes, SQL optimization, locks, etc., corresponding to intermediate work.
In the future, there will be some advanced knowledge such as log management, master-slave replication, sub-database and sub-table, and read-write separation.
Maybe this passage is a little difficult for you who are just getting started, but it doesn’t matter, we will explain it to you later.
So we can divide the database knowledge into 3 parts, gradually study in depth, and strive to become a database master as soon as possible~
2 Getting Started with MySQL - Concepts related to MySQL
1. What is a database?
A database is actually a warehouse for storing data, which stores data in an organized manner. Its corresponding word is DataBase, which we generally refer to as DB for short.
2. What is a database management system?
The data has been saved in the database, so we need to further operate and manage the data in the database. This requires the corresponding software to assist. The corresponding word is DataBase Management System, which we call DBMS for short. In fact, you don’t need to feel it Difficult, in fact, this is a software, you will know that it is actually very simple when you introduce it later.
TIPS: For example, the MySQL database we are learning now is a database management system DBMS, but for convenience among programmers, the MySQL database management system is referred to as the MySQL database for short.
3. What is SQL?
In order to facilitate the operation of the database, we have defined a set of standard programming languages for operating relational databases. Its corresponding word is Structured Query Language (Structured Query Language), which we generally call SQL.
We can operate the database management system through SQL, and then operate the data in the database through the database management system.
TIPS: The "relational" mentioned here will be explained later, you can skip it now
4. What are the commonly used relational database management systems?
The picture below shows the ranking of databases on DB-Engines.com:
the database we want to learn here is MySQL, and you don’t have to worry about it. I haven’t learned how to deal with so many databases. SQL is used to operate the database, and the SQL statement is a unified standard for operating the database.
The following content is not the focus, and those who are interested can briefly understand:
- Oracle is a large fee-based database of Oracle Corporation, and the software and subsequent service charges are relatively expensive
- MySQL was a free database belonging to Sun in the early days, and later Sun was acquired by Oracle, so now MySQL also belongs to Oracle. After Oracle acquired MySQL, it was
upgraded, and a paid version of MySQL was produced. Free community edition of MySQL.- SQL Server is a medium-sized database developed by Microsoft, and it is also charged
- PostgreSQL is a small and medium-sized open source free database
- MongoDB is a distributed file storage database written in C++ language, between relational database and non-relational database
- IBM Db2 is a fee-based database
- Redis is a cross-platform non-relational database that uses the Key-Value storage system
- SQLite embedded micro-database, Android's built-in database is the choice