PHP shopping cart example (Shenjing)_PHP tutorial

if(! $session && ! $scid) {
/*
session is used to distinguish each shopping cart, which is equivalent to the ID number of each cart;
scid is only used to identify a shopping cart id number, which can be regarded as the name of each cart;
When both the id and session value of the shopping cart do not exist, a new shopping cart is generated
*/
$session = md5( uniqid(rand()));
/*
Generate a unique shopping cart session number
rand() first generates a random number, and uniqid() then generates a unique one based on the random number string, and finally md5 the string
*/
SetCookie(scid, $session, time() + 14400);
/*
Set the shopping cart cookie
variable Name: scid (I wonder if there is a $ sign missing here? =》Correction: Add "" to scid)
Variable value: $session
Valid time: current time + 14400 seconds (within 4 hours)
For detailed usage of the setcookie function, please refer to the PHP manual~
*/
}
class Cart { //Start shopping cart class
function check_item( $table, $session, $product) {
/*
Check item (table name, session, item)
*/
$query = SELECT * FROM $table WHERE session=' $session' AND product=' $ product' ;
/*
Look at the 'table' to see if there is the 'product' in the 'shopping cart'
That is, whether the product has been put into the shopping cart
*/
$result = mysql_query( $query);
if(! $result) {
return 0;
}
/*
Query failed
*/
$ numRows = mysql_num_rows( $result);
if( $numRows == 0) {
return 0;
/*
If not found, return 0
*/
} else {
$row = mysql_fetch_object( $result);
return $row->quantity;
/*
If found, return the quantity of the item
It is necessary to explain mysql_fetch_object here Function (will be used below):
[mysql_fetch_object() is similar to mysql_fetch_array(), with one difference - it returns an object instead of an array.】
The above sentence is taken from the PHP manual, it should be very clear~
To put it simply, to get a certain field in a record, you should use "->" instead of using it like an array. Subscript
*/
}
}
function add_item( $table, $session, $product, $quantity) {
/*
Add new item (table name, session , item, quantity)
*/
$qty = $this->check_item( $table, $session, $product);
/*
Call the above function and check the class first Has the item been put into the car?
*/
if( $qty == 0) {
$query = INSERT INTO $table (session, product, quantity) VALUES ;
$query . = (' $session', ' $product', ' $quantity') ;
mysql_query( $query);
/*If it is not in the car, add the item to the car*/
} else {
$quantity += $qty; //If there is, increase the quantity on the original basis
$query = UPDATE $table SET quantity=' $quantity' WHERE session=' $session' AND ;
$query .= product=' $product' ;
mysql_query( $query);
/*
and modify the database
*/
}
}
function delete_item( $table, $session, $product) {
/*
Delete item (table name, session, item)
*/
$query = DELETE FROM $table WHERE session=' $ session' AND product=' $product' ;
mysql_query( $query);
/*
Delete items of this type in the shopping cart
*/
}
function modify_quantity( $table, $session, $product, $quantity) {
/*
Modify item quantity (table name, session, item, quantity)
*/
$query = UPDATE $table SET quantity =' $quantity' WHERE session=' $session' ;
$query .= AND product=' $product' ;
mysql_query( $query);
/*
Modify the quantity of this item For the value in the parameter
*/
}
function clear_cart( $table, $session) {
/*
Clear the shopping cart (nothing to say)
*/
$query = DELETE FROM $table WHERE session=' $session' ;
mysql_query( $query);
}
function cart_total( $table, $session) {
/*
cart Total price of items in
*/
$query = SELECT * FROM $table WHERE session=' $session' ;
$result = mysql_query( $query);
/*
First Take out all items in the car
*/
if(mysql_num_rows( $result) > 0) {
while( $row = mysql_fetch_object( $result)) {
/*
If items If the quantity is > 0 pieces, then judge the price one by one and calculate
*/
$query = SELECT price FROM inventory WHERE product=' $row->product' ;
$invResult = mysql_query( $query) ;
/*
Find the price of the item from the inventory table
*/
$row_price = mysql_fetch_object( $invResult);
$total += ( $row_price-> ;price * $row->quantity);
/*
Total price += price of the item * quantity of the item
(you should be able to understand)
*/
}
}
return $total; //Return the total price
}
function display_contents( $table, $session) {
/*
Get detailed information about all items in the car
*/
$count = 0;
/*
Item quantity count
Note that this variable is not only used to count the number of items, but more importantly, it will be used as a return value The subscript in the array is used to distinguish each item!
*/
$query = SELECT * FROM $table WHERE session=' $session' ORDER BY id ;
$result = mysql_query( $query);
/*
Take out the cart first All items in
*/
while( $row = mysql_fetch_object( $result)) {
/*
Get detailed information for each item separately
*/
$query = SELECT * FROM inventory WHERE product=' $row->product' ;
$result_inv = mysql_query( $query);
/*
Find information about this item from the inventory table
*/
$row_inventory = mysql_fetch_object( $result_inv);
$contents[product][ $count] = $row_inventory->product;
$contents[price][ $count] = $row_inventory->price;
$contents[quantity][ $count] = $row->quantity;
$contents[total][ $count] = ( $row_inventory->price * $row ->quantity);
$contents[description][ $count] = $row_inventory->description;
/*
Put all the detailed information about the item into the $contents array
$contents is a two-dimensional array
The first set of subscripts distinguishes different information about each item (such as item name, price, quantity, etc.)
The second set of subscripts distinguishes different items (this This is the function of the $count variable defined earlier)
*/
$count++; //The number of items plus one (i.e. the next item)
}
$total = $this->cart_total( $table, $session);
$contents[final] = $total;
/*
At the same time, call the cart_total function above, calculate the total price
and put it into the $contents array
*/
return $contents;
/*
Return the array
*/
}
function num_items( $table, $session) {
/*
Returns the total number of item types (that is, it seems nonsense to count two identical items as one - -!)
*/
$query = SELECT * FROM $table WHERE session=' $session' ;
$result = mysql_query( $query);
$num_rows = mysql_num_rows( $result);
return $num_rows;
/*
Take out all the items in the car and get the effects of the operation The number of database rows, that is, the total number of items (nothing to say)
*/
}
function quant_items( $table, $session) {
/*
Returns the total number of all items (that is, , two identical things are also counted as two items - -#)
*/
$quant = 0;//Total quantity of items
$query = SELECT * FROM $table WHERE session=' $session ' ;
$result = mysql_query( $query);
while( $row = mysql_fetch_object( $result)) {
/*
Fetch each item one by one
*/
$quant += $row->quantity; //The quantity of the item is added to the total quantity
}
return $quant; //Return the total quantity
}
}