4. MySQL tutorial

Mysql

MySQL is the most popular relational database management system, and MySQL is one of the best RDBMS (Relational Database Management System: relational database management system) applications in WEB applications.

In this tutorial, you will quickly grasp the basic knowledge of MySQL and easily use the MySQL database.

4.1. What is a database?

Database (Database) is a warehouse that organizes, stores and manages data according to the data structure.

Each database has one or more different API for creating, accessing, managing, searching, and replicating saved data.

We can also store data in a file, but it is relatively slow to read and write data in the file.

So now we use a relational database management system (RDBMS) to store and manage large amounts of data. The so-called relational database is a database based on the relational model, which deals with the data in the database with the help of mathematical concepts and methods such as set algebra.

RDBMS is the characteristics of relational database management system (Relational Database Management System):

  • 1.数据以表格的形式出现

  • 2.每行为各种记录名称

  • 3.每列为记录名称所对应的数据域

  • 4.许多的行和列组成一张表单

  • 5.若干的表单组成database

4.2. RDBMS terminology

  • 4.2.17. MySQL LIKE clause

    We know that we use the SQL SELECT command in MySQL to read data, and we can read data in the SELECT Statement to get th...
    2025-10-25 13:32:52 UTC

  • 4.2.19. MySQL sorting

    We know that SQL SELECT statements are used to read data from the MySQL table. If we need to sort the read data, we can us...
    2025-10-25 13:32:49 UTC

  • 4.2.20. MySQL GROUP BY statement

    The GROUP BY statement groups the result set according to one or more columns. We can use COUNT, SUM, AVG, and other funct...
    2025-10-25 13:32:51 UTC

  • 4.2.21. Use of MySQL connections

    In the previous chapters, we have learned how to read data in one table, which is relatively simple, but in real application...
    2025-10-25 13:32:50 UTC

  • 4.2.22. MySQL NULL value processing

    We already know that MySQL uses the SQL SELECT command and the WHERE clause to read the data in the data table, but when the...
    2025-10-25 13:32:50 UTC

  • 4.2.24. MySQL transaction

    MySQL transactions are mainly used to deal with data with large amount of operations and high complexity. For example, in th...
    2025-10-25 13:32:50 UTC

  • 4.2.25. MySQL ALTER command

    When we need to change the data table name or modify the data table field, we need to use the MySQL ALTER command. 开始本章教程前...
    2025-10-25 13:32:51 UTC

  • 4.2.26. MySQL index

    The establishment of MySQL index is very important for the efficient operation of MySQL, and the index can greatly improve t...
    2025-10-25 13:32:51 UTC

  • 4.2.27. MySQL temporary table

    MySQL temporary tables are very useful when we need to save some temporary data. Temporary tables are visible only in the cu...
    2025-10-25 13:32:48 UTC

  • 4.2.28. MySQL copy table

    If we need to completely copy the MySQL data table, including the table structure, index, default value, etc. If you only us...
    2025-10-25 13:32:49 UTC

  • 4.2.29. MySQL metadata

    You may want to know the following three messages about MySQL: 查询结果信息： The number of records affected by the SELECT, U...
    2025-10-25 13:32:50 UTC

  • 4.2.30. MySQL sequence usage

    MySQL sequence is a set of integers: 1, 2, 3,. Because a data table can only have one field self-increasing primary key, if ...
    2025-10-25 13:32:48 UTC

  • 4.2.31. MySQL handles duplicate data

    There may be duplicate records in some MySQL data tables, and in some cases we allow duplicate data, but sometimes we also n...
    2025-10-25 13:32:50 UTC

  • 4.2.32. MySQL and SQL injection

    If you get the data entered by the user through a web page and insert it into a MySQL database, then the security problem of...
    2025-10-25 13:32:50 UTC

  • 4.2.33. MySQL export data

    In MySQL, you can use SELECT…INTO OUTFILE Statement to simply export data to a text file. Use SELECT… INTO OUTFILE stat...
    2025-10-25 13:32:51 UTC

  • 4.2.34. MySQL Import data

    In this section, we introduce several simple MySQL import data commands.
    2025-10-25 13:32:52 UTC
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