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

  • 4.2.18. MySQL UNION operator

    This tutorial introduces you to the syntax and examples of the MySQL UNION operator. Description ...
    2023-12-29 23:00:02 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 da...
    2025-10-25 12:31:20 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, an...
    2025-10-25 12:31:22 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 appli...
    2025-10-25 12:31:21 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 wh...
    2025-10-25 12:31:20 UTC

  • 4.2.23. MySQL regular expression

    In the previous chapter, we have learned that MySQL can be accessed through the LIKE …% To make a fuzzy...
    2025-10-25 12:23:39 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,...
    2025-10-25 12:31:21 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. ...
    2025-10-25 12:31:22 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 imp...
    2025-10-25 12:31:23 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 ...
    2025-10-25 12:31:18 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 o...
    2025-10-25 12:31:20 UTC

  • 4.2.29. MySQL metadata

    You may want to know the following three messages about MySQL: 查询结果信息： The numbe...
    2025-10-25 12:31:21 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 ke...
    2025-10-25 12:31:18 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 ...
    2025-10-25 12:31:21 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 prob...
    2025-10-25 12:31:21 UTC

  • 4.2.33. MySQL export data

    In MySQL, you can use SELECT…INTO OUTFILE Statement to simply export data to a text file. ...
    2025-10-25 12:31:22 UTC
Principles and Applications of WebGIS  37

IT Tools  337

Web Frameworks  49

Principles, Technologies, and Methods of Geographic Information Systems  102

In recent years, Geographic Information Systems (GIS) have undergone rapid development in both theoretical and practical dimensions. GIS has been widely applied for modeling and decision-making support across various fields such as urban management, regional planning, and environmental remediation, establishing geographic information as a vital component of the information era. The introduction of the “Digital Earth” concept has further accelerated the advancement of GIS, which serves as its technical foundation. Concurrently, scholars have been dedicated to theoretical research in areas like spatial cognition, spatial data uncertainty, and the formalization of spatial relationships. This reflects the dual nature of GIS as both an applied technology and an academic discipline, with the two aspects forming a mutually reinforcing cycle of progress.

WEB Technology  258

Systems  232

Programming Language  353