Skills for integrating Linux applications into my SQL database (1)

This article describes MySQL, an effective tool for developing electronic trade and other complex and dynamic websites using third-party databases. MySQL is a fast, multi-threaded, and fully functional SQL Server. In addition to describing the basic architecture of the MySQL system, this article also provides simple examples written in Tcl and C ++ to help you develop Web applications that support databases. An application that must store or access a large amount of information can benefit from using third-party database products. This is especially true when access to information must be performed on multiple instances of the program. Web-based applications, including electronic trade, are good examples.

Why is an independent database used?

The Web server must have a processing script to store the status information for future access. Although it is possible to use more primitive methods-such as dumping to text files or developing self-made mini databases-only mature database applications can provide all the services required by more complex Web applications. Because some free software packages can be used for this purpose, writing custom application-specific database engines is not very advantageous. In addition, the use of third-party databases also frees Web developers from investing in database development and maintenance tasks.

MySQL database

By using the script language and compiled system language such as C), it is quite easy to integrate the database into a Linux application. MySQL is available free of charge under the GNU Public License.) The database provides a series of complex SQL functions and is easy to integrate into applications. MySQL is fast and multithreading and supports ANSI and odbc SQL standards. With third-party software, MySQL supports transaction security tables for transaction processing applications.

Note: What is transaction processing?

A transaction is a series of changes made to the database that need to be performed in an atomic manner. Either they must be executed in full or none of them. For example, when selling products on the Web, all necessary database changes constitute a transaction. The database needs to deduct the customer account balance and product inventory at the same time, otherwise the operation fails and is not executed. No matter what causes the server to crash, the transaction should not be partially executed. For example, billing calculation, product delivery, or inventory inaccuracy may be the result of partially completed transactions. A database that supports transaction processing can encapsulate a set of database code in a transaction. Any failure during transaction execution will cause the database to roll back to the state before the transaction starts. This is achieved by maintaining logs of all database operations and copies of their original status tables. rollback is allowed when the server is restarted next time after a failure. This time and space overhead is a necessary compromise for the transaction security database system. A single MySQL server controls a series of databases, which can be accessed through the server in a similar way. Each database is actually a group of any number of tables, similar to other SQL database users. Each table is composed of data columns with data types. The data can be an integer, real value, string, or other type, including the original binary stream. Each row in the table is a record stored in the database.

MySQL is designed and constructed as a client/server. The server mysqld can run on any machine that can be accessed from the Internet. It is best to run on the same or closest server as the Web server to ensure a reasonable response time ). The MySQL client uses a request to contact the MySQL server to modify or query the database owned by the server. In Web applications that support databases, database clients are Web servers or CGI scripts generated by Web servers. These clients can be written in advanced scripting or low-level system languages, as long as there is a database API in this language. In Linux, most scripting languages are implemented in C. because MySQL c apis exist, it is easy to add MySQL support to any existing scripting language or tool. Most scripting languages have completed this step.