General code design question...

rebelo

Traditionally in user-based web applications, I've used various functions to do access level checks or retreive user values, etc. For example:

getUserLevel() would look up the user in the database and return their access level
getUserValue($value) would look up the user in the database and return whichever key you specify
getUserInfo($userid) would grab the entire row for that user and return it as an associative array.

Because I am trying to start optimizing my code a bit better, I am wondering if perhaps instead of doing database checks for all these sorts of things, I would be better off just doing a single routine at the start of the script which reads the entire users table into an associative array so that subsequent calls to that information will not incur the overhead of extra database queries. The downside, of course, is the extra memory usage, especially if the user table gets very large.

Any ideas on which is going to the better solution in the long-run?

I know it's not a technical question, I'm just interested in hearing some other opinions.

bbreslauer

If you do all of those calls on the same page, in the same page loading (i.e. you don't refresh the page), then it might be slightly faster, though I'm not sure. If you're refreshing the page every time, then this will actually be slower, because you incur the overhead of writing the array each time.

This brings up an interesting question, and one that I'm not all that knowledgeable on. I'd be interested to here other's opinions as well.

halojoy

hey

for most I can think of
it is only for ADMIN purpose you would need All your Users Data Table
in this case you can get all user table
into a 1 multidimensional array
or several smaller arrays in Admin SESSION variables

for any single logged in user/member normal User SESSION
you can, to reduce database calling time and script load,
put this current user's record into a session array

and from there you can in whatever page/function
faster and without DB-call get any data field regarding this user

still in both cases, for update of any user data
of course, you need to call Db to store new values

it is a good idea to use SESSION for storing data used frequently
instead of doing many small database operations to get data
But I shouldnt store too much, large blocks of data in session
in such case it may be more wise to work directly with DB

/halojoy

rebelo

Hi Halojoy,

I am certainly in agreement with the usefulness of SESSION variables, however they are not appropriate for this usage. It is necessary to call the user related data from the database on every page (whether it's all at once in an array or as needed through individual query functions), because if an admin makes a change to a user's account (such as suspending their account or changing their access permissions), these changes need to take effect immediately so that users cannot "ride the session" and potentially get around access limitations which may have been set in place while they were logged in.

halojoy

rebelo wrote:
Hi Halojoy,

I am certainly in agreement with the usefulness of SESSION variables, however they are not appropriate for this usage. It is necessary to call the user related data from the database on every page (whether it's all at once in an array or as needed through individual query functions), because if an admin makes a change to a user's account (such as suspending their account or changing their access permissions), these changes need to take effect immediately so that users cannot "ride the session" and potentially get around access limitations which may have been set in place while they were logged in.

I see.
If we do not want to have current work data
in database table storage file
and not in session temp file
and being afraid being short of working system memory
than
we have not much options left.

It is perfectly easy to store any two or more dimensions arrays
in Flat Text files in your harddrive.

If was a possiblilty to store in memory, this would be much better
and the method to use if only possible!,
because ordinary harddrives are slow compared with any sort of memory
(50 MHz to 1000 MHz, a factor like 10-20!)
and as database MySQL or Flat or whatever also uses files,
things can not happen faster than harddrive
can read and transfer data to php.exe or any other program.

Anyway to store in a temp workfile in drive
makes data solid, whatever page you are on,
and does not care if you are in a session or not - it is like having data in database.
But this way data is a bit closer to you - with no database middle-hands - go-betweens.
You have total control what is done with your data array.

Here is way I sometimes use for store array variables in file,
for easy recovering and working with data.
Even if you probably knows this very well,
we have many other readers and eager php code learners
who could have good use for this method.

<?php

// Write '$data' array to a file "tempfile.data". 
// serialize array and write binary 

$fp=fopen('tempfile.data','wb'); 
fwrite($fp,serialize($data)); 
fclose($fp); 


// Read Back '$data' array from file "tempfile.data". 
// read binary and unserialized into array '$data'

$fp=fopen('tempfile.data','rb'); 
$data = unserialize(fread($fp,filesize('tempfile.data'))); 
fclose($fp);

?>

The above fwrite does not use my file locking function for flat files.
But if this is an issue, I have posted the code of lock file while write elsewhere at forum.
A few minutes of search phpbuilder forum would give that function code
to anyone in need.

halojoy - one dimesional man with many ideas

🙂

Weedpacket

I don't see what the benefit of reading in the whole users' table might be: it won't reduce the amount of checking that needs doing, and it will increase the amount of data that needs to be transferred between the DBMS and PHP.

Even if you did fetch the entire user table into PHP, you'd still need to store it somewhere and read it in again on subsequent pages. And you'd still have to query the database again on the next page anyway, to prevent session riding, as you've noted.

And meanwhile, all that irrelevant data regarding other users is sitting there in PHP, taking up space.

So I'd stick to querying what is needed as and when it is needed. As long as you're not wasting time repeatedly opening and closing connections several times a page (e.g., within each of your querying functions), you shouldn't have grief.

One thing you could do would be to design a user object, with properties for everything relevant you have about the user, and methods for querying those properties, and also for querying the database to populate it in the first place (which last method you would run when you've established the db connection).

It wouldn't matter if they get B& while they're viewing the page they're looking at, because as soon as they try to do anything further, a fresh query of the user table would be made and their undesirable status would be revealed.

halojoy

Weedpacket wrote:
I don't see what the benefit of reading in the whole users' table might be: it won't reduce the amount of checking that needs doing, and it will increase the amount of data that needs to be transferred between the DBMS and PHP.

Even if you did fetch the entire user table into PHP, you'd still need to store it somewhere and read it in again on subsequent pages. And you'd still have to query the database again on the next page anyway, to prevent session riding, as you've noted.

And this was also my first and main wondering some posts ago in this topic:

halojoy wrote:
for most I can think of
it is only for ADMIN purpose you would need All your Users Data Table
in this case you can get all user table
into a 1 multidimensional array
or several smaller arrays in Admin SESSION variables

for any single logged in user/member normal User SESSION
you can, to reduce database calling time and script load,
put this current user's record into a session array

and from there you can in whatever page/function
faster and without DB-call get any data field regarding this user

Now if we could understand what special needs our friend rebelo has,
and what this is that we others can not figure out, yet

Can it be that we are not too smart and clever ????
A frightening ans scaresome thought ........

🙂 🙂