MySQL Study Notes 02-database overview and MySQL Introduction

Databases are closely linked to daily applications. Before databases become available, people manually record and process various information. When a large amount of information needs to be recorded, the efficiency of manual processing becomes very low. For example, when a patient goes to a hospital for medical treatment, a series of procedures such as registration, medical treatment, Drug Buying, hospitalization, treatment, and rehabilitation are required. The name, gender, and age of the patient must be registered. When buying medicines, the hospital selects the medicines that meet the requirements from thousands of medicines based on the Drug List. The hospital needs to know the name, location, inventory, and access of the medicines. If there are many patients, it will be annoying for the hospital to choose medicine. If it is manually processed, the workload is high, and it is possible to take the wrong medicine. In this case, if you use a database, you only need to enter the drug name to know the specific location, inventory, and other details. This is convenient, improves efficiency, and avoids taking the wrong medicine.

The superiority of databases can only be displayed when the organization and management information is large or complex and the manual processing is extremely heavy. Of course, large companies that process millions of businesses each day can use databases. However, even small companies that only involve individual personal interests who maintain information may need databases. It is not hard to imagine that using the database will bring more benefits if the following situations occur:

■ Your company has several hundred employees. You need to save the personal information and salary records of each employee so that you can know who paid the salary and when, and you must summarize these records so that you can report the income to the tax authority. You also need to understand what your company hires and what you make for each job.

■ You are a teacher and need to know the credits and attendance information. Each time you take a test or test, you must record the credits of the students. It is easy to write your exam scores in the workbook, but it will be very difficult to use it in the future and you need to review it on one page. It is not a simple task to calculate the absence of absenteeism for each student.

Generally, we use a database management system to process tasks such as file cabinets. In a sense, a database is like a large file cabinet, just a built-in file orchestration system. Electronic processing records have many advantages over manual processing records. For example, if you work in an office facility that stores customer records, the database management system can help you in some ways:

■ Reduce the recording and archiving time. You do not have to view all the drawers in the cupboard to find new records. You just need to put the recording into the file orchestration system and make the file orchestration system put the record in the correct position for you.

■ Reduce the record retrieval time. When searching for records, you do not need to search for each record to find the record containing the required information. Assume that you work in a dental clinic. If you want to send a reminder to all patients who have not recently performed a diagnosis, you only need to ask the file orchestration system to find the appropriate records. Of course, this is different from asking others to do it. You only need to say, "Please confirm which patients have not been there in the last six months ."

Database application systems mainly include databases (databases), database management systems (DBMS), and database applications. The relationship between the three parts is shown in figure 2.1.

The actual database may be quite complex, and the operations on the database will be more complex. I managed and operated databases more effectively, and people developed a database management system (DBMS ). DBMS is a software product that people use to operate databases. Oracle, ms SQL Server, MySQL, Sybase, Foxpro, access, and so on are all in the DBMS category. Although the functions of these DBMS products vary, the basic functions are similar.

MySQL is one of the popular relational databases. Compared with other database management systems (DBMS), MySQL has the advantages of being small, complete, and fast in query, the key is that it is free, can be downloaded to the Internet for free, and can be used for free, suitable for medium and small applications, or even large applications.

The official website for MySQL is: http://www.mysql.com. There are many technical support websites. If you encounter problems during the learning process, you can go to the following websites for support:

Http://www.linuxforum.net/

Http://www.csdn.com/

Http://tech.ccidnet.com/pub/column/c1108.html

The most important thing is:

Http://www.google.com/

Http://www.baidu.com/

 

 

(Note: For reprint and reference, please indicate the author saulzy)