PHP - POST & GET

Recall from the PHP Forms Lesson where we used an HTML form and sent it to a PHP web page for processing. In that lesson we opted to use the the post method for submitting, but we could have also chosen the get method. This lesson will review both transferring methods.

POST - Review

In our PHP Forms Lesson we used the post method. This is what the pertinent line of HTML code looked like:

HTML Code Excerpt:

This HTML code specifies that the form data will be submitted to the "process.php" web page using the POST method. The way that PHP does this is to store all the "posted" values into an associative array called "$_POST". Be sure to take notice the names of the form data names, as they represent the keys in the "$_POST" associative array.
Now that you know about associative arrays, the PHP code from "process.php" should make a litte more sense.

PHP Code Excerpt:

$quantity = $_POST['quantity'];
$item = $_POST['item'];

The form names are used as the keys in the associative array, so be sure that you never have two input items in your HTML form that have the same name. If you do, then you might see some problems arise.

PHP - GET

As we mentioned before, the alternative to the post method is get. If we were to change our HTML form to the get method, it would look like this:

HTML Code Excerpt:

The get method is different in that it passes the variables along to the "process.php" web page by appending them onto the end of the URL. The URL, after clicking submit, would have this added on to the end of it:
"?item=##&quantity=##"
The question mark "?" tells the browser that the following items are variables. Now that we changed the method of sending information on "order.html", we must change the "process.php" code to use the "$_GET" associative array.

PHP Code Excerpt:

$quantity = $_GET['quantity'];
$item = $_GET['item'];

After changing the array name the script will function properly. Using the get method displays the variable information to your visitor, so be sure you are not sending password information or other sensitive items with the get method. You would not want your visitors seeing something they are not supposed to!

Security Precautions

Whenever you are taking user input and using you need to be sure that the input is safe. If you are going to insert the data into a MySQL database, then you should be sure you have thought about preventing MySQL Injection. If you are going to make a user's input available to the public, then you should think about PHP htmlentities.

PHP functions - eregi

eregi() -   became deprecated starting PHP 5.3.0

hmmm... I've used this function many times.

Time and Date - PHP

PHP has the ability to dynamically generate the time and date. Using a simple line of code we are able to include this on our site, however it is important to know how the formatting works.



You can use the date function in conjunction with the time function to display this in the format of date ( format , time ) In our case we want the start time to be now, so we will call the time first. We will demonstrate many different types of formatting


 $b = time (); 
 print date("m/d/y",$b) . "
"; 
 print date("D, F jS",$b) . "
"; 
 print date("l, F jS Y",$b) . "
"; 
 print date("g:i A",$b) . "
"; 
 print date("r",$b) . "
"; 
 print date("g:i:s A D, F jS Y",$b) . "
"; 
 ?> 


There is different formats that can be used in the date feature. Below is a summary of the variable used in date, and what each does. They ARE CaSe sEnsItIVe:


DAYS 
d - day of the month 2 digits (01-31) 
j - day of the month (1-31) 
D - 3 letter day (Mon - Sun) 
l - full name of day (Monday - Sunday) 
N - 1=Monday, 2=Tuesday, etc (1-7) 
S - suffix for date (st, nd, rd) 
w - 0=Sunday, 1=Monday (0-6) 
z - day of the year (1=365)


WEEK 
W - week of the year (1-52)


MONTH 
F - Full name of month (January - December)
m - 2 digit month number (01-12) 
n - month number (1-12) 
M - 3 letter month (Jan - Dec) 
t - Days in the month (28-31)


YEAR
L - leap year (0 no, 1 yes)
o - ISO-8601 year number (Ex. 1979, 2006)
Y - four digit year (Ex. 1979, 2006)
y - two digit year (Ex. 79, 06)


TIME
a - am or pm
A - AM or PM
B - Swatch Internet time (000 - 999)
g - 12 hour (1-12)
G - 24 hour c (0-23)
h - 2 digit 12 hour (01-12)
H - 2 digit 24 hour (00-23)
i - 2 digit minutes (00-59)
s 0 2 digit seconds (00-59)


OTHER e - timezone (Ex: GMT, CST)
I - daylight savings (1=yes, 0=no)
O - offset GMT (Ex: 0200)
Z - offset in seconds (-43200 - 43200)
r - full RFC 2822 formatted date

Basic PHP Syntax video

http://video.about.com/php/Basic-PHP-Syntax.htm

Mysql Temporary tables

he temporary tables could be very useful in some cases to keep temporary data. The most important thing that should be knows for temporary tables is that they will be deleted when the current client session terminates.

Temporary tables where added in MySQL version 3.23. If you use an older version of MySQL than 3.23 you can't use temporary tables, but you can use heap tables.

As stated earlier temporary tables will only last as long as the session is alive. If you run the code in a PHP script, the temporary table will be destroyed automatically when the script finishes executing. If you are connected to the MySQl database server through the MySQL client program, then the temporary table will exist until you close the client or manually destroy the table.

Example

Here is an example showing you usage of temporary table. Same code can be used in PHP scripts using mysql_query() function.

mysql> CREATE TEMPORARY TABLE SalesSummary ( -> product_name VARCHAR(50) NOT NULL -> , total_sales DECIMAL(12,2) NOT NULL DEFAULT 0.00 -> , avg_unit_price DECIMAL(7,2) NOT NULL DEFAULT 0.00 -> , total_units_sold INT UNSIGNED NOT NULL DEFAULT 0 ); Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO SalesSummary -> (product_name, total_sales, avg_unit_price, total_units_sold) -> VALUES -> ('cucumber', 100.25, 90, 2); mysql> SELECT * FROM SalesSummary; +--------------+-------------+----------------+------------------+ | product_name | total_sales | avg_unit_price | total_units_sold | +--------------+-------------+----------------+------------------+ | cucumber | 100.25 | 90.00 | 2 | +--------------+-------------+----------------+------------------+ 1 row in set (0.00 sec)

When you issue a SHOW TABLES command then your temporary table would not be listed out in the list. Now if you will log out of the MySQL session and then you will issue a SELECT command then you will find no data available in the database. Even your temporary table would also not exist.

Dropping Temporary Tables:

By default all the temporary tables are deleted by MySQL when your database connection gets terminated. Still you want to delete them in between then you do so by issuing DROP TABLE command.

Following is the example on dropping a temproary table.

mysql> CREATE TEMPORARY TABLE SalesSummary ( -> product_name VARCHAR(50) NOT NULL -> , total_sales DECIMAL(12,2) NOT NULL DEFAULT 0.00 -> , avg_unit_price DECIMAL(7,2) NOT NULL DEFAULT 0.00 -> , total_units_sold INT UNSIGNED NOT NULL DEFAULT 0 ); Query OK, 0 rows affected (0.00 sec) mysql> INSERT INTO SalesSummary -> (product_name, total_sales, avg_unit_price, total_units_sold) -> VALUES -> ('cucumber', 100.25, 90, 2); mysql> SELECT * FROM SalesSummary; +--------------+-------------+----------------+------------------+ | product_name | total_sales | avg_unit_price | total_units_sold | +--------------+-------------+----------------+------------------+ | cucumber | 100.25 | 90.00 | 2 | +--------------+-------------+----------------+------------------+ 1 row in set (0.00 sec) mysql> DROP TABLE SalesSummary; mysql> SELECT * FROM SalesSummary; ERROR 1146: Table 'TUTORIALS.SalesSummary' doesn't exist