Thank you Jasper,

this also sounds like an interesting approach.
But creating tables on the fly brings me to the idea, that I can also enlarge one table on the fly. Then I could consider the function as a matrice and store it in only one table, which can be enlarged dynamically.


I am very new to PHP and havn't programmed for a decade now.
But thank you all (Bastien, Shawn, Jasper) for your comments. Probably I will implement all and run then some articifial performance tests agains the different versions.
But this will take me weeks or months until I am so far.

And I hoped some new non-relational DB technology could solve the challenges I described, but probably not.
Cheers,
Ben


Jasper Mulder schrieb:
----------------------------------------
Date: Wed, 11 May 2011 22:15:21 +0200
From: benedikt.vo...@web.de
To: nos...@mckenzies.net
CC: php-general@lists.php.net
Subject: Re: [PHP] Re: Storing indefinite arrays in database

Thanks Shawn,

yes, your second idea works for me. The first one not, as I need to
search and join on it.
To continue your second idea with your example:

Arguments:
id results_id variable value
1 1 1 800
2 1 2 999
3 1 3 3.14

Results:
id result
1 50
2 99

The Arguments and Results table would be filled dynamically by user content.
In order to run a function, I have to do N times a join, whereas N is the 
number of arguments:

select result
from Results join Arguments as A1 join Arguments as A2 join Arguments as A3
on Results.id=A1.results_id and
on Results.id=A2.results_id and
on Results.id=A3.results_id and
where
A1.variable=1 and A1.value=800 and
A2.variable=2 and A2.value=999 and
A3.variable=3 and A3.value=3.14 and
A1.results_id=Results.results_id and
A2.results_id=Results.results_id and
A3.results_id=Results.results_id

Theoretically this works, but how good will be the performance if there are 
Thousands of entries?
Anyway, I will try out.
Thanks again,
Ben

Dear Ben,

Firstly, as this is my first post to this list I apologize for any etiquette 
mistakes.

I would like to suggest to you a different approach, which would be more 
dynamical:
First, you would have a table which stores the number of arguments of a certain 
entry, something like

    record_id   num_of_arg

You would store the num_of_arg entry in a PHP variable, say $num.
Then you would proceed to use

   "CREATE TABLE IF NOT EXISTS \'entries_".$num."\' ...some more code..."

to create a table which can store precisely $num arguments per record.
Then you add it to that table using standard MySQL.
Effectively this groups all records into tables according to $num.

The only thing here is that you probably need to call the database two times:
  - first to get num_of_arg to be able to call onto the right table
  - second to get the data

But as the number of arguments would go into the thousands, no huge join would 
be necessary.
Only thing is, that you would have very wide tables (I don't know how wide 
MySQL can go).

Creating tables on-the-fly as necessary seems to be something you could 
consider,
but again I stress that I don't know performance details. There might be 
something quicker.

So far for my 2c. Hopefully, it is of some help.

Best regards,
Jasper Mulder
                                        



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