[Q] Store the shopping basket

soken

Hi,
I want to make a shopping cart, but I don't know how to store the shopping basket. Should I use sessions only or use both of sessions and database to store it? Because somebody said it spends lot of resource if using sessions only.

If customer adds three products in basket and I use both of sessions and database, is the database structure like this?

======================================

| id | sessionid | product | quantity |

| 1 | f4cb5cb468fb51fb75c1fdd2f | dc | 1 |
| 2 | f4cb5cb468fb51fb75c1fdd2f | book | 5 |

| 3 | f4cb5cb468fb51fb75c1fdd2f | cd | 3 |

Please correct my concept. Thanks!

drew010

im not sure where the logic of only using sessions takes more resources. it would seem to me using sessions would take x resources, and then using sessions and db would use x + y resources. if you do wish to use both, the table structure you have is right on. just use their session id as a reference and store the info in the database rather than in a $_SESSION variable. the only problem is you will have to implement some kind of cleanup method that will remove old sessions out of the database if the user doesnt checkout. so you will have to add an extra time field and perhaps have a cronjob run to see if there are sessions in the db older than x hours and if so delete them.

soken

Originally posted by drew010
im not sure where the logic of only using sessions takes more resources. it would seem to me using sessions would take x resources, and then using sessions and db would use x + y resources. if you do wish to use both, the table structure you have is right on. just use their session id as a reference and store the info in the database rather than in a $_SESSION variable. the only problem is you will have to implement some kind of cleanup method that will remove old sessions out of the database if the user doesnt checkout. so you will have to add an extra time field and perhaps have a cronjob run to see if there are sessions in the db older than x hours and if so delete them.

Thanks your reply! 🙂

I'm thinking method to remove old sessions from database...
if session.cache_expire is 180, does it mean that session will be deleted after 180 mins from the start of making session? 😕

I save the time when making session, and I write the program which will check and delete when record is over 180 mins. Is it efficient? Because I afraid that the record is deleted but session is not deleted.

drew010

the variable you would want to use for that is the session.cookie_lifetime one.

"session.cookie_lifetime specifies the lifetime of the cookie in seconds which is sent to the browser. The value 0 means 'until the browser is closed.'"
the cache expire one just tells the browser how long to cache a session page for, so for example if they hit a back button beyond the cache expire it will give that "page has expired" message.

soken

Originally posted by drew010
the variable you would want to use for that is the session.cookie_lifetime one.

"session.cookie_lifetime specifies the lifetime of the cookie in seconds which is sent to the browser. The value 0 means 'until the browser is closed.'"
the cache expire one just tells the browser how long to cache a session page for, so for example if they hit a back button beyond the cache expire it will give that "page has expired" message.

Thanks to correct my mistake! 🙂

Now, the problem is database, if I set session.cookie_lifetime to "0", how to delete the record in database if user closes the browser? I think it isn't useful to set the time to keep the record in database, because user may be shopping over the time of keeping the data in database.

Anyway, I want to know the session question, is it possible that the session id is repeat again if the session id is occur before and break now?

drew010

if you do set cookie_lifetime to 0, i would recommend using a field in the database that stores when the last time data was updated for a specific session id. then you can implement a cleanup script, perhaps run by cron every 12 hours or something, that will delete entries where the last update hasnt been for a day or so.

tekky

simply set a table in the database with the access time of the sessionID using a unixtimestamp

then on each page request you cou ld simply

//semi-pseudo code
SELECT * FROM sessionTimeouts WHERE lastUpdate < (now()-3600)
while( $row = mysql_fetch_array($result))
{
  //each of this is now a timedout session (longer older than 1hr)
  //delete it or whatever you want to do with it...
}

Weedpacket

Or write session handlers so that the database is used to store session data....

soken

Originally posted by drew010
if you do set cookie_lifetime to 0, i would recommend using a field in the database that stores when the last time data was updated for a specific session id. then you can implement a cleanup script, perhaps run by cron every 12 hours or something, that will delete entries where the last update hasnt been for a day or so.

Thanks everybody, you all are so nice and help me so much! 🙂 I'll try to make up it, I hope all of you don't mind if I have any problem and ask you again. :p

Finally, can anybody can tell me the last session question? The session id (for example, 12333) is existed before, but it is broken now. If I session start again, is it possible that the session id (12333) repeat again? How does making of session id depend on?

Weedpacket

Originally posted by soken
Finally, can anybody can tell me the last session question? The session id (for example, 12333) is existed before, but it is broken now. If I session start again, is it possible that the session id (12333) repeat again? How does making of session id depend on?

Well, the session ID looks more like 07671a038c0eb43723d421693b073c3b, and is generated by taking the current time on the server (to within a millisecond), some values from a random number generator, and (optionally, specified in php.ini) bits from an external entropy supply. It is highly unlikely that a given session ID will repeat in the lifetime of a site; and even less likely that a new session ID will be generated that happens to match an old session ID for which session data is still being stored.

soken

Originally posted by Weedpacket
Well, the session ID looks more like 07671a038c0eb43723d421693b073c3b, and is generated by taking the current time on the server (to within a millisecond), some values from a random number generator, and (optionally, specified in php.ini) bits from an external entropy supply. It is highly unlikely that a given session ID will repeat in the lifetime of a site; and even less likely that a new session ID will be generated that happens to match an old session ID for which session data is still being stored.

Sorry, you mean that a new session id will not repeat the old session id which is still existed, but will a new session id repeat the old session id if old session id is not existed now? Sorry, I disturb you again.

Weedpacket

Originally posted by soken
Sorry, you mean that a new session id will not repeat the old session id which is still existed, but will a new session id repeat the old session id if old session id is not existed now? Sorry, I disturb you again.

I mean that it's unlikely that any given session ID will be repeated ever. There are just too many possible session IDs (on the order of 3×10³⁸⁾ for it to be likely that the same one will be picked at random twice.

soken

Originally posted by Weedpacket
I mean that it's unlikely that any given session ID will be repeated ever. There are just too many possible session IDs (on the order of 3×10³⁸⁾ for it to be likely that the same one will be picked at random twice.

I understand now, many thanks for your help! 🙂