Php 101 by David Menendez

1. PHP-101
A beginners guide to programming with PHP
By David Menendez

2. Variables
 A variable is used to represent a piece
of information in terms that the
computer can understand
 Types of variables include:
◦ Integers = Numbers
◦ Strings = Letters and Numbers
◦ Boolean = True / False
◦ Array = Variable that contains many
variables

3. Syntax
 Syntax is simply the language of the
program
 Syntax is the grammar used to get the
program to run properly
 Without proper grammar the program
is doomed to fail!

4. Syntax Cont.
 Let‟s start a PHP file
◦ Begin every PHP file by opening a PHP
bracket
◦ To open the bracket simply start with-
<?PHP
◦ To end the bracket type- ?>
◦ Ending Bracket = <?PHP ?>
◦ The code goes in-between

5. Syntax Cont.
 Variable Syntax-
◦ How we declare a variable
◦ Begin every variable with a dollar sign $
◦ Next we add the name- $variable
◦ Finally we give it a value- $variable = 50;
 Always remember to end all of your
statements with a semicolon; It is how
the program knows the command is
over

6. Syntax Cont.
 How to make sure you have declared
your variable properly
◦ Echo = very useful PHP function
◦ Echo to show the value of your variable
◦ Ex-
 $variable = 5;
 Echo $variable;
 Output on the web page = 5

7. Databases
 Let‟s connect to a database!
 Start by declaring variables-
◦ $connection = mysql_connect();
 This variable is using the mysql_connect
function to aid us in the connection.
 This function requires 3 inputs within the ().
 Server Name
 User Name
 Password
◦ $connection = mysql_connect(„localhost‟,
„root‟, „password‟);

8. Databases
 More variables!
◦ Select a database-
 $database = mysql_select_db();
◦ Completed variable-
 $database =
mysql_select_db(„database_name‟,
$connection);

9. Database Language
 Now we just need to learn a little
MYSQL to work with databases. Don‟t
worry, it‟s not hard.
 Pull the information from a table
◦ Select all from Table_name(„field_name‟);
◦ Now you have all the information from that
table.
◦ Put it in PHP-
 $query = “SELECT all from TABLE („field‟,
„field‟, field‟);”;

10. PHP and the Web
 One more vital function for web work
 If / Else statements
 Based on a certain condition
 If X = 1 than go left, If X = 2 go right.
 Syntax-
◦ If(condition){outcome};

11. PHP and the Web
 Let‟s put it all together!
◦ Declare your database variables
◦ Open up your PHP bracket
◦ Time to generate dynamic content!

12. Dynamic Content
 Use logic and functions to think up
endless possibilities
 Let‟s start with random pictures
 Important function to making this work
is the Rand() function
◦ Rand() Generates a random number
between any number you give it.
 Ex- Rand(1,100) will not generate a random
number between 1 and 100.

13. Dynamic Content Cont
 Get some images
◦ To make this work be sure to end each file
name with a number. Pic1.jpg, pic2.jpg,
etc etc
 Declare a variable with rand()
◦ $random = rand(1,3);

14. Dynamic Content Cont
 Put it all together
◦ <?php
◦ $random = rand(1,3);
◦ Echo “Img src=„image” . $random “.jpg‟>”;
◦ ?>

15. Dynamic Content Cont
 So what happened?
◦ We declared a variable for a random
number
◦ We used the echo function to show the
image
◦ Now every time this runs it will generate a
random number, place the number at the
end of the image and show that image

16. End
 Now you should have a very basic
understanding of the PHP language.
 There is a lot more out there to learn
about PHP and programming.
 If you want to learn more visit
www.php.net