Programming with php
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Programming with php
By: Seth Larson
A little bit about PHP
PHP stands for PHP:
Hypertext Preprocessor
PHP is a widely-used general-purpose server-side
scripting language that is suited for Web
development and can be embedded into HTML.
PHP scripts are executed on the server
PHP supports many different databases (MySQL,
Informix, Oracle, Sybase, Solid, PostgreSQL, Generic
ODBC, etc.)
PHP is an open source software (OSS), so its free
PHP files have a file extension of ".php", ".php3", or
".phtml"
PHP files are returned to the browser as plain HTML
Server Side
o
o
o
o
o
<html>
<body>
<?php echo '<p>PHP rules!</p>';?>
</body>
</html>
Client Side
<html>
<body>
<p>PHP rules!</p>
</body>
</html>
What do you need installed on your
computer to use php?
A server that supports php. Some
servers that support php are
Apache(open source), IIS
(Microsoft), and Oracle.
The latest version of PHP found at
http://www.php.net
You can test if php is installed and
working with the following code.
Show php information
<html>
<body>
<?php
phpinfo();
?>
</body>
</html>
Some PHP syntax
A php statement always begins
with <?php and ends with ?>.
php statements can be placed
anywhere in the document.
Statements end with semicolon.
PHP variables
Variables start with $, example $var
Variables have the same syntax rules as
other high level languages.
To concatenate two or more variables
together, use the dot (.) operator:
Using the “\” right next to a variable
name tells the server to print what
directly follows and not to treat it as a
label.
Sample Variables
<html>
<body>
<?php
$var_A = " Print \$var_A ";
$var_B = "To print a variable name instead
of what the variable is holding use the \
character.";
echo $var_B;
echo"<P>";
echo $var_A;
?>
</body>
</html>
PHP operators
Arithmetic Operators
+, -, /, *
Assignment Operators
=, +=, -=, *=, /=, %=
Comparison Operators
==, !=, >, <, >=, <=
Logical Operators
&&, ||, !
If – else statement
if (condition)
code to be executed
else
code to be executed
While
while
{
Do-while
do
{
For
Foreach
code to be executed;
code to be executed;
}
}
while (condition);
PHP forms
Form is created with html.
Any html element you put in a form is
available after a submit because php
automatically makes element variables.
Examples:
$_POST["first"],$_POST["last"
Notice that if you use post in the form
header the variables are accessible with
$_POST, if you use get the variables are
accessible with $_GET.
Form
<html>
<body>
<form action="php_forms_next.php" method="post">
<pre>Your Id: <input type = "text" name = "id"/>
</ br>
Your First name: <input type="text" name="first" />
</ br>
Your Last name: <input type="text" name="last" />
<?php
echo "male: <input type = checkbox name = sex value
male>
Female: <input type = checkbox name= sex
value=female>
?>
<input type="submit" /></pre>
</form>
</body>
</html>
Print form variables
<html>
<body><pre>You said your Id number was:
<?php echo $_POST["id"]; ?></pre>
<pre>You said your First name was <?php echo
$_POST["first"]; ?></pre>
<pre>You said you Last name was <?php echo
$_POST["last"]; ?></ pre>
<pre>You also said you are <?php echo
$_POST["sex"];?></pre>
<pre>Your favorite color is <?php echo
$_POST["color"];?></pre>
</body>
</html>
Text File Read/Write
<html>
<body>
<?php
if (!($file=fopen("php_file.txt","r")))
exit("Can’t open file.");
while (!feof($file))
{ $char=fgetc($file);
echo $char;
}
//$write = fputs($fp, “write hi”);
fclose($file);
?>
</body>
</html>
Using a database
The mysql_connect() function opens a link to a
MySQL server on the specified host along with a
username (root) and a password.
mysql_select_db() is used to tell my MySQL to
use the specified database.
mysql_query()sends a line of SQL to the MySQL
database identified in the connection for
processing. The returned results are stored in
$result.
mysql_result() is used to display the values of
fields from our query.
%s indicates that the variable in the second half
of the expression (e.g.,
mysql_result($result,0,"position")) should be
treated as a string and printed.
Reading one field from each record in
the database
<html>
<body>
<?php
$db = mysql_connect("localhost", "root","seth");
mysql_select_db("mydb",$db);
$result = mysql_query("SELECT * FROM employee",$db);
$count=mysql_numrows($result);
$i=0;
while ($i < $count)
{
printf("First Name: %s",
mysql_result($result,$i,"first"));
echo "<p>";
$i++;
}
mysql_close();
?>
</body>
</html>
Reading records one at a time
<html>
<body>
<?php
$db = mysql_connect("localhost", "root", "seth");
mysql_select_db("mydb",$db);
$result = mysql_query("SELECT * FROM employee",$db);
echo "<table border=1>\n";
echo "<tr><td>id</td><td>First Name and Last
Name</td></tr>\n";
while ($myrow = mysql_fetch_row($result))
{
printf("<tr><td>%s </td><td>%s %s</td></tr>\n",
$myrow[0], $myrow[1], $myrow[2]);
}
echo "</table>\n";
?>
</body>
</html>
Inserting into a Database: form part
<html>
<body>
<form action="php_insert_form_insert.php" method="post">
<pre>
Your Id: <input type = "text" name = "id"/>
Your First name: <input type="text" name="first" />
Your Last name: <input type="text" name="last" />
</br>
<input type="submit" /></pre>
</form>
</body>
</html>
Insert into a MySQL database
<html><body>
<?php
$id = $_POST["id"];
$first = $_POST["first"];
$last = $_POST["last"];
$db = mysql_connect("localhost", "root","seth");
mysql_select_db("mydb",$db);
$result = mysql_query("SELECT * FROM employee",$db);
echo "<table border=1>\n";
echo "<tr><td>id</td><td>First Name and Last Name</td></tr>\n";
while ($myrow = mysql_fetch_row($result))
{
printf("<tr><td>%s </td><td>%s %s</td></tr>\n",
$myrow[0], $myrow[1], $myrow[2]);
}
echo "</table>\n";
$query = "INSERT INTO employee VALUES ('$id','$first','$last')";
mysql_query($query);
?>
</body>
</html>
