Differentiate between NULL and 0

[GazK]

I have a script which takes the results of a form and updates or creates
a record in a db table. So far so dull. It works fine, except when I
leave certain fields blank; these are entered in the table as zero
values. Can anyone assist me to differentiate between NULL and zero? the
variables that are troubling are fatalities, injuries, latitude and
longitude.

TIA

Garry

code:

# load variables into array
$variables["type"] = $type;
$variables["location"] = $location;
$variables["fatalities"] = $fatalities;
$variables["injuries"] = $injuries;
$variables["latitude"] = $latitude;
$variables["longitude"] = $longitude;
$variables["development"] = $development;
$variables["list"] = $list;
$variables["display"] = $display;
$variables["description"] = $description;

foreach ($variables as $key => $value) {
# loop through variables;
$element =& $variables[$key];
if (isset($value)) {
# if variable is not null, add quotes for sql query
$element = "'" . $element . "'";
} else {
# variable is NULL - no quotes
$element = "NULL";
}
unset($element);
}

# explode array back to variables
extract($variables);

if(isset($eventID)) {
# updating an existing record
# create SQL from variables
$sql = "
UPDATE tblevents
SET enumType = $type,
locationID = $location,
datDate = '$eventDate',
intFatalities = $fatalities,
intInjuries = $injuries,
dblLatitude = $latitude,
dblLongitude = $longitude,
developmentID = $development,
enumList = $list,
enumDisplay = $display,
txtDescription = $description
WHERE eventID = $eventID
";
} else {
# creating a new record
$sql = "
INSERT INTO tblevents (
eventID,
enumType,
locationID,
datDate,
intFatalities,
intInjuries,
dblLatitude,
dblLongitude,
developmentID,
enumList,
enumDisplay,
txtDescription
) VALUES (
NULL,
$type,
$location,
'$eventDate',
$fatalities,
$injuries,
$latitude,
$longitude,
$development,
$list,
$display,
$description
)
";
}

# execute SQL
mysql_query($sql) or die(mysql_error());

[askMe]

GazK wrote:

I have a script which takes the results of a form and updates or creates
a record in a db table. So far so dull. It works fine, except when I
leave certain fields blank; these are entered in the table as zero
values. Can anyone assist me to differentiate between NULL and zero? the
variables that are troubling are fatalities, injuries, latitude and
longitude.

TIA

Garry

Zero is a number. NULL has no value assigned.

http://www.askblax.com

[GazK]

askMe wrote:

GazK wrote:

I have a script which takes the results of a form and updates or creates
a record in a db table. So far so dull. It works fine, except when I
leave certain fields blank; these are entered in the table as zero
values. Can anyone assist me to differentiate between NULL and zero? the
variables that are troubling are fatalities, injuries, latitude and
longitude.

TIA

Garry

Zero is a number. NULL has no value assigned.

http://www.askblax.com

Thanks, thats given me the answer; insert a test for
is_numeric($variable) on these items. Thanks again.

[Tim Van Wassenhove]

On 2006-01-15, GazK <ru*****@rubbish.com> wrote:

Thanks, thats given me the answer; insert a test for
is_numeric($variable) on these items. Thanks again.

if ($variable !== 0) {
// ...
}
--
Met vriendelijke groeten,
Tim Van Wassenhove <http://timvw.madoka.be>

[Tony Marston]

The easiest way I have found to test for the existence or non-existence of a
value in the $_POST array, and to avoid any confusion between empty, null
and zero, is to use the strlen() function. If the result is a length of
zero, then it signifies no input. Easy peasy lemon squeezy.

--
Tony Marston

http://www.tonymarston.net

"GazK" <ru*****@rubbish.com> wrote in message
news:4M********************@eclipse.net.uk...

I have a script which takes the results of a form and updates or creates a
record in a db table. So far so dull. It works fine, except when I leave
certain fields blank; these are entered in the table as zero values. Can
anyone assist me to differentiate between NULL and zero? the variables that
are troubling are fatalities, injuries, latitude and longitude.

TIA

Garry

code:

# load variables into array
$variables["type"] = $type;
$variables["location"] = $location;
$variables["fatalities"] = $fatalities;
$variables["injuries"] = $injuries;
$variables["latitude"] = $latitude;
$variables["longitude"] = $longitude;
$variables["development"] = $development;
$variables["list"] = $list;
$variables["display"] = $display;
$variables["description"] = $description;

foreach ($variables as $key => $value) {
# loop through variables;
$element =& $variables[$key];
if (isset($value)) {
# if variable is not null, add quotes for sql query
$element = "'" . $element . "'";
} else {
# variable is NULL - no quotes
$element = "NULL";
}
unset($element);
}

# explode array back to variables
extract($variables);

if(isset($eventID)) {
# updating an existing record
# create SQL from variables
$sql = "
UPDATE tblevents
SET enumType = $type,
locationID = $location,
datDate = '$eventDate',
intFatalities = $fatalities,
intInjuries = $injuries,
dblLatitude = $latitude,
dblLongitude = $longitude,
developmentID = $development,
enumList = $list,
enumDisplay = $display,
txtDescription = $description
WHERE eventID = $eventID
";
} else {
# creating a new record
$sql = "
INSERT INTO tblevents (
eventID,
enumType,
locationID,
datDate,
intFatalities,
intInjuries,
dblLatitude,
dblLongitude,
developmentID,
enumList,
enumDisplay,
txtDescription
) VALUES (
NULL,
$type,
$location,
'$eventDate',
$fatalities,
$injuries,
$latitude,
$longitude,
$development,
$list,
$display,
$description
)
";
}

# execute SQL
mysql_query($sql) or die(mysql_error());