Chapter 23
Using a Database
In This Chapter
- Introducing MySQL
- Introducing PostgreSQL
- Creating database objects
- Writing database shell scripts
One of the problems with shell scripts is persistent data. You can store all the information you want in your shell script variables, but at the end of the script, the variables just go away. There are times when you'd like for your scripts to be able to store data that you can use later. In the old days, to store and retrieve data from a shell script required creating a file, reading data from the file, parsing the data, and then saving the data back into the file. Search for data in the file meant reading every record in the file to look for your data. Nowadays with databases being all the rage, it's a snap to interface your shell scripts with professional-quality open source databases. The two most popular open source databases used in the Linux world are MySQL and PostgreSQL. This chapter shows you how to get these databases running on your Linux system and then spends some time getting you used to working with them from the command line. It then goes on to show you how to interact with each one using normal bash shell scripts.
The MySQL Database
By far the most popular database available in the Linux environment is the MySQL database. Its popularity has grown as a part of the Linux-Apache-MySQL-PHP (LAMP) server environment, which many Internet Web servers use for hosting online stores, blogs, and applications.
This section describes ...
