Page 4: Abstraction
Use PHP Functions not DB Functions!
Hopefully by now you are beginning to get the idea of why query result sets are useful. The point is this, if you extract your results into an array, like the ones shown above, you no longer need to play around with lots of different types of database specific functions in order to work with extracted data. The only functions you need to use (99.9% of the time) are PHP functions. The really great thing about this is that you can be darn sure that your code is much more portable between databases. Another benefit is that you need so much less code! (Which is, of course, great news if you're a lazy sod like me.)
Lets look at some 'meat and potato' ways to work with query result sets using built-in PHP functions, bearing in mind that the result sets are in the same format as the ones described above.
Count how many rows of results have been returned
Print all results
foreach ( $results as $result )
Print one row of results
Print one variable from one row of results
Re-sort results (sorts on first element of second dimension)
assort($results); // or any other sort function
Now that we have defined our main atomic functions and we have a new way of working with query results, we need a nice new code library that turns all the standard database gunk into a few neat, atomic functions. If we do this correctly, the only code we will ever need to write again is:
1) A little bit of code to send a query to the database
And that, my friends, is a lazy sod's dream come true.
2) A little bit of code to deal with results
But Where's the Class?
What we really need is a PHP class that does all of the above and makes it very easy to do so. You guessed it, it just so happens that I've already made one! Of course, you don't have to use it -- you're welcome to make your own -- but for the sake of this article I am going to use it as an example of how to be as lazy as possible when working with databases.
The class in question is called ezSQL and is available from http://php.justinvincent.com. To install it, you'll need to:
1) Download it.
2) Change the database settings at the top of it.
3) Include it in the start of your PHP script.
You don't need to worry about what ezSQL is actually doing. All you need to know is that it takes care of gunk. It deals with connections, row fetching, freeing space, etc. Let's have a look at how easy it is to print out some results using this new class:
$users = $db->get_results("SELECT * FROM users");
foreach ( $users as $user )
As you can see, the new class takes care of everything gunk related. The connection stuff happens simply by including the class in the first place. The only thing we need to do is use one simple function that takes a SQL query as an argument and outputs a query result set. From that point forward, we simply use PHP functions to work with the data.