In this hour, you learned how to use include() to incorporate files into your documents and execute any PHP code contained in include files. You learned how to use some of PHP's file test functions and explored functions for reading files by the line, by the character, or in arbitrary chunks. You also learned how to write to files, either replacing or appending to existing content. Finally, you learned how to create, remove, and read directories.
Now that you can work with files, you can save and access substantial amounts of data. If you need to look up data from large files, however, your scripts will begin to slow down quite considerably. What you need is some type of database. In the next hour, we will look at PHP's DBA functions, which provide relatively fast access to data on file systems.