Optimizing PHP/MySQL

[Anon]

I am trying to optimize a a PHP/MySQL site.

I need to know a couple of things. I want to hit the db as little as possible, so I am using arrays to store values. When I do my initial call to the db to get info, I do this:

http://www.mydomain.com/?id=12345
(This is how a user typically arrives at the site.)

I check the id against the db:

$my_array = mysql_fetch_row(mysql_query("select * from table_name where id = '$id'"));

Here is my question:

Is the db queried when I define the variable, or when I call the variable?

(ie: echo "$my_array[0]"; )

If it queries when I use the variable, does it query MySQL every time I use the variable or just the first time so I can use the values in the array without querying again?

I want to grab all the info on my member when they come in only one time. Then, I want to use that array multiple times without hitting the db each time I need the data.

Thanks

[Anon]

One more question.

Can I pass the array in a hidden field to the next page?

Thanks

[lawnmowerman]

The database is only queried when you actually use mysql_query().

You could serialize the array and pass it in a hidden field, but you'd be better off using sessions and register the array with the session, or simply query the database each time the page loads. As long as your indexes on the database are properly designed your queries are efficient (don't return all 300 fields froma table when you only need 3 of the fields, etc), you shouldn't have any problems.

Hope this helps....

-Rich

[Anon]

Thanks Rich.

[lawnmowerman]

No problem 🙂

-Rich