PEAR DB::getOne question

[Markus Ernst]

Hi

I wondered what the return value of the getOne method in the PEAR DB class
is when no row is found:

$what = $db->getOne("SELE CT field FROM table WHERE 1=2");
if($what=="") echo "emptystrin g";
if($what==false ) echo "false";
if($what==NULL) echo "null";
echo $what;

echoes "emptystringfal senull". Is it possible that the function returns a
value that is an empty string, false and null at the same time?

If I want to check for the existence of a row, is it okay to check for
either of the three possibilities, or is there a preferred one?

$id = $db->getOne("SELE CT id FROM table WHERE condition='fulf illed');

// this one?
if($id=="") do_something();
// or this one?
if($id==false) do_something();
// or that one?
if($id != NULL) do_something();

else do_something_el se($id);


Thanks for every hint.

--
Markus

[Berislav Lopac]

Re: PEAR DB::getOne question

Markus Ernst wrote:[color=blue]
> Hi
>
> I wondered what the return value of the getOne method in the PEAR DB
> class is when no row is found:
>
> $what = $db->getOne("SELE CT field FROM table WHERE 1=2");
> if($what=="") echo "emptystrin g";
> if($what==false ) echo "false";
> if($what==NULL) echo "null";
> echo $what;[/color]

Either use === in the above if statements, or simply replace them with
var_dump($what) .

Berislav

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[Markus Ernst]

Re: PEAR DB::getOne question

Berislav Lopac wrote:[color=blue]
> Markus Ernst wrote:[color=green]
>> Hi
>>
>> I wondered what the return value of the getOne method in the PEAR DB
>> class is when no row is found:
>>
>> $what = $db->getOne("SELE CT field FROM table WHERE 1=2");
>> if($what=="") echo "emptystrin g";
>> if($what==false ) echo "false";
>> if($what==NULL) echo "null";
>> echo $what;[/color]
>
> Either use === in the above if statements, or simply replace them with
> var_dump($what) .
>
> Berislav[/color]

Thank you - that makes a difference indeed.

--
Markus

[Michael Fesser]

Re: PEAR DB::getOne question

.oO(Markus Ernst)
[color=blue]
>Berislav Lopac wrote:
>[color=green]
>> Either use === in the above if statements, or simply replace them with
>> var_dump($what) .[/color]
>
>Thank you - that makes a difference indeed.[/color]

The reason is the automatic typecasting of PHP. All '', FALSE and NULL
evaluate to FALSE, so in your case all three if-statements are
successful.

The === operator not only compares the values, but also the types.

Micha