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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
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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 • <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 { code to be executed; } • Do-while • do { code to be executed; } while (condition); • For • Foreach
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>