In this chapter, we have shown you how to go from entering SQL queries in a simple database server client program to having these queries execute within your PHP scripts. In addition to showing you the basics of connecting to a database server and authenticating a user, we showed you the rest of the basic operationsfetching data, modifying data, inserting and deleting data, and performing transactions. We also had the chance to look at prepared statements, which help us reduce the amount of data we send over the connection to the database server when we execute the same queries.
We did all of this with the new MySQL extension available in PHP5, which includes a spiffy object-oriented interface for our convenience. However, we have shown the older procedural interface in action since this is how we will interact with servers such as PostgreSQL, Oracle, and Microsoft's SQL Server.
This concludes Part II, "Database Basics." In the next part, we will spend some time on theory, looking at what web applications are and how to approach major areas of functionality, such as user interface, user management, and security.
In the next chapter, we begin with an overview of what web applications are and how they are put together from a high-level view.