Is there really no "current_row" in PHP?

glowball

I've searched these boards and can't find a definitive answer. I primarily use ColdFusion and enjoy query.CurrentRow in a few applications. I've used ASP before and used AbsolutePage and PageSize to work with chunks of a recordset. Is there no equivalent in PHP? I know I can use LIMIT to get a piece out of MySQL but will PHP not do this for me no matter what database I'm using?

Sorry if this is discussed somewhere else, if it is I couldn't find it.

Thanks!

Anon

Rather than a built-in database abstraction layer, PHP ships with a bunch of database-specific modules. The downside, of course, is lack of universality. The upside is you get to work with a set of functions that more closely match the database's view of how to do things.

If you're using mysql (as you appear to hint at) then go see the mysql function pages at php.net, as well as the very comprehensive manual on mysql itself at mysql.com.

In short, there's nothing exactly equivalent to CF, but there are many ways to accomplish the same thing, mosly relying on the fact that most methods of retrieving mysql data involve reading one row at a time from the result set.

mattee

For mysql there is this function:

http://www.php.net/manual/en/function.mysql-insert-id.php

for mssql, (after an insert for instance) use
SELECT @@IDENTITY AS last_id;
(yet anothe obtuse micro$oft way of doing things)

I'm sure other databases have yet more ways of handling sequences. Search the php.net site for your database and find the docs for it. Then you can see if there's a built in php way to get the sequence results you want.

You should also look into phplib
http://sourceforge.net/projects/phplib
The library abstraction layer abstracts the sequence process so that all sequences across all databases are handled the same way through a "sequence" table.

Then you use the phplib sequence handlers and don't have to mess around with database specific sequence handlers.

glowball

I finally just put in a counter that increments in the loop -- works just fine of course but I was really curious about built-in functionality. Thanks for the info!

glowball

I was looking for a "current row" in a result set from a select statement, but this answers other questions I had so that works -- thanks!

Anon

Just curious: what to you need this for?

glowball

In the interest of saving time I was going to rewrite some of my apps in PHP that are currently in ColdFusion (a fairly good search utility being one of them). It uses CurrentRow, among other things. Then I started wondering about doing the "color every other row" thing and wondered how you would do it without a CurrentRow (and without implementing a counter). After looking around this forum I wasn't sure if there was a CurrentRow equivalent or not so I thought I'd ask.

It's not something I need but something I want -- but I can work around it.

mattee

Hrm, you know, I don't actually think I understand what current row does in Cold Fusion. I thought I did, but I don't. If you explain what it does, then perhaps I'll be able to make sense of it in a php way.

glowball

Using the simple process of coloring every other row, for example, CurrentRow makes things very simple. Every query returns a few "pseudo-columns" (I think that's what they're called), things like CurrentRow and RecordCount that hold info about the recordset. When ColdFusion sends a SQL Statement to the database it has a name, so the returned records are "name.column" when you want to call on them. You just loop through the recordset like you do in PHP. CurrentRow is just like a column in how you call it, so "name.CurrentRow" with each loop is a new number. First loop is 1, second loop is 2, etc.

So in English,

"if name.CurrentRow is odd, color it. If it's even, don't color it"

I just do this using MOD (same as %) to find if it's even or odd.

So you can see how easily this can extend to getting chunks out of a recordset, say for pages of a search. I just pass p=2 in the URL for page 2 of the search and if I know how many rows I want per page it's simple math to get rows 11 through 20. CurrentRow will reflect this with each loop, starting at 11 and ending with row 20.

I know that was a lengthy explanation, but I hope it was helpful!