NYCPHP Meetup

[Dan Cech]

Ophir Prusak wrote:
> Hi All,
> 
> I've been tasked with a project that I think is applicable to almost 
> every web based application:
> Giving the user the ability to add custom fields to their data / forms.
> After doing some thinking, I realized that the "engine" for such a 
> feature could be totally generic and work for almost any web site.
> I looked on freshmeat, sourceforge and phpclasses but didn't see 
> anything really geared toward this functionality.
> 
> For example:
> Your client is a large car rental service and they wanted an intranet 
> app that allows them to keep inventory of all their cars.
> Users enter make, model, color, year, A/C, miles, location, etc.
> After it's launched, the Dallas office wants to add a field for ground 
> clearance (in inches) and four wheel drive (checkbox).
> The Miami office wants fields for Hitch (checkbox) and Engine Size 
> (pulldown).
> You get the picture.
> 
> What have you done or would you do when faced with this requirement ?
> Is this something you are in need of as well ?
> Comments / Suggestions ?
> 
> I'm considering starting an open source project for this. I got an OK 
> from my boss if it means other people will help out :).
> Are there other developers here who would be interested in joining a 
> project like this ?

I haven't seen anything geared directly towards this, but it can 
definitely be done.

The approach I like to take when building my applications is to try and 
design all my database related code to be able to work with any number 
of columns:

function load ($id)
{
	$sql = 'SELECT * FROM mytable WHERE id=' $db->qstr ($id);
	$rs = $db->SelectLimit ($sql,1);
	if ( !is_object ($rs) )
	{
		return FALSE;
	}
	
	return $rs->FetchRow ();
}

That is a fairly basic example, but you see that you can simply add an 
extra field in the database and it will automatically be added.

Another approach to this problem from a database perspective is to add a 
table to hold these extra pieces of data, with columns id, att and val. 
  That gets a little more complicated in the load and save routines, but 
is very good when you have extra data which is only applicable to a 
small subset of your objects.

As for the forms, I did write an app a while ago which could generate 
multipage forms from definitions stored in a database, which would allow 
them to be edited through a web interface, that approach worked very 
well for me, might even be able to dig up a copy if anyone is interested...

Dan