Storing and Retrieving Data

NOW THAT WE KNOW HOW TO access and manipulate data entered in an HTML form,
we can look at ways of storing that information for later use. In most cases, including the
example we looked at in the previous chapter, you’ll want to store this data and load it
later. In our case, we need to write customer orders to storage so that they can be filled
later.
In this chapter we’ll look at how you can write the customer’s order from the previous
example to a file and read it back.We’ll also talk about why this isn’t always a good
solution.When we have large numbers of orders, we should use a database management
system such as MySQL.
Key topics you will learn about in this chapter include
n Saving data for later
n Opening a file
n Creating and writing to a file
n Closing a file
n Reading from a file
n File locking
n Deleting files
n Other useful file functions
n Doing it a better way: database management systems
n Further reading