Re: [Mysql-cocoa-users] testing for a NULL value from the db

[John G. <jo...@jl...>]

This came up a while ago (a long time ago) and I can't exactly remember 
the outcome, also I am using an old version of the framework at the 
moment.

the NSNull is a special Cocoa object to represent Null items.

you can do something like

if ([[row objectForKey:@"COMMENT"] isKindOfClass:NSNull])
{
	// process the null object properly
}

I think that should help
(have a look at the Cocoa documentation for NSObject for isKindOfClass)

JOhn


On 22 Jul 2004, at 17:14, John Spicer wrote:

> I have some rows in the database table that are nulls.
>
> I am trying to do an assignment like this:
>
> 			[thisOne setCOMMENT:[row objectForKey:@"COMMENT"]];
>
>
> but later on in assignments to elements I get an error of
>
> *** -[NSNull length]: selector not recognized
>
> since it's a null and not a string.
>
> How do I test this coming from the db and set it to an empty string?
>
> I tried this
>
> 		if ([row objectForKey:@"COMMENT"] != NULL)
>
>
> but it's not a null, it's an object with a name of NSNull which I 
> don't know how to deal with!
>
> Help!