Simple guide to PHP coding

[Andy]

Quick tip for debugging MySQL database problems:

If you get an invalid result resource error, it means that your query is malformed. It is nothing to do with zero rows of data being found.

In the PHP documentation you will see verbose MySQL query examples that do too much error checking in my opinion. As long as your code produces valid queries, you should never see the invalid resource error. And if you do see these errors, so will your users, even if you report the errors to the browser.

So all you need to check for is number of rows returned after a "select" query and number of affected rows after other queries if you need to know.

p.s. I always form my query in a string before executing the mysql_query() function since it is very easy to insert an echo or die to view the offending query when de-bugging your code e.g.

Code:

<?php
$q = "SELECT `name` FROM `categories` WHERE `id`='$cat'";
                echo "Q: $q "; // Debug it
                die("Q: $q "); // Or break at this point
connect_to_db();
$r = mysql_query($q);
?>

Once the problem is resolved, I remove any debug code like this.

[Andy]

One aspect of coding SQL queries that I avoided until now was how to combine 2 tables into one query. The standard MySql documentation is difficult to understand I think.

The easy way to understand how to do it is explained at this web site:
http://www.halfgaar.net/sql-joins-are-easy

 

[Andy]

To get started in PHP you could try this simple code to display the current year in your web template:

Code:

<?php echo date("Y"); ?>

This is useful next to your copyright symbol.

[donecweb]

To get started in PHP you could try this simple code to display the current year in your web template:

Code:

<?php echo date("Y"); ?>

This is useful next to your copyright symbol.

Wouldn't you want to use the first date you copyrighted it?

[Andy]

Wouldn't you want to use the first date you copyrighted it?

You can show a range of years from the 1st year to the current year. That seems to be a common practice.