Easy question?

krausem

Hopefully this is an easy question. I have a PHP webform and I need to have the form enter a NULL value into a column, if NULL is select from a drop down list. All I keep coming up with is an empty value, but not a NULL value.

For example the HTML form code is

<p align="left">Manufacturer's Name:
<select name="HOUSING_MANUF_NAME" id="HOUSING_MANUF_NAME">
<option selected>NULL</option>
<option>Enlight</option>
<option>Other</option>
</select>

and the PHP code is

if ($HOUSING_MANUF_NAME == 'NULL') {
$HOUSING_MANUF_NAME = NULL;
}

I have also tried some other PHP code such as

if ($HOUSING_MANUF_NAME == 'NULL') {
$HOUSING_MANUF_NAME = '';
}

but cannot get the form to put a NULL value into the database. I always just get an empty value i.e. ''

Any ideas on how I would do this? I would appreciate any help you can give me. Thanks.

raymie

I assume that you have made sure that the database field is actually allowed to have nulls.

if so then you need to make sure that the sql for inserting or amending the record uses NULL and not a text value.

for example

insert into table (field) values (NULL);

update table set field=NULL;

do that and all should be well.

krausem

The fields are set up correctly, because it works if I do an insert NULL from the command line. I just don't know the PHP code to get the form to enter a NULL into the field, it always just makes it a blank or puts a text NULL in the field.

raymie

I just gave you the code....

You need to set the field to NULL as per the examples i gave. not set it to a text value....

krausem

I'm missing something then. How do I code the problem:

If the NULL option is selected, enter NULL into the field. So if a text "NULL" is detected, set the variable to regular NULL

Please excuse my ignorance. I am finding it hard to explain what I need. Thank you for your patience.

ednark

ummm... php NULL and sql NULL have nothing to do with each other

you would have to give the literal string 'NULL' in the database query something like tfis

$id = 2;
$val = NULL;

if ( strlen($val) > 0 ) {
     /// if its a string wrap it in quotes for sql
    $val = "'$val'";
} else if ( $val === NULL ) {
    /// if its null set the string to null
    $val = "NULL";
}


$sql = "
UPDATE 
    table
SET
    column = $val
WHERE
    column_id = $id
";

this will produce two outputs, depending on what $val is

1) column = 'value'
2) column = NULL

krausem

Hmmm...that isn't working either. It just keeps setting the variable to a text NULL. My field is NULL by default, so if the form detected a NULL value, leaving the variable out of the insert statement would work too, because without it seeing a variable, it would just use the default NULL. Wonder how I would code that.

raymie

What I initially suggested and what was paraphrased by the last poster is correct and does work.

If you are not getting it to work then your database is either not set up properly as you assert, or your are not implementing the suggesion correctly.

I would suggest that rather than just keeping to post 'it doesn't work' that you should post an exact example and the relevant code extract.

ednark

what i did was just an exmple of what raymie's suggested.
and i also agree that if you are still confused please post code so someone can help more specifically

freakyfreak

is it just me or do those <option>'s need a value ?
ie <option value="NULL"> NULL</option>

BLottman

either way it should associate the value="NULL" or value=NULL with the name="description"

(i.e., $description) on submit.