Inserting when NULL

[RynMan]

Hey guys

 

So I've built a form with various text fields, radio buttons, and text areas.  Now I want to be able to use the data collected from that form and INSERT it into my table using PHP. 

 

On the next page (the action=) page from my form, I set up the INSERT query, however it runs into a problem when I don't enter a value into a field on the form on the previous page. 

 

It's because I'm using the $variable = $_POST["postedvariable"] method, and since nothing was entered, nothing is posted, and the query fails since there is no value. 

 

I'm wondering how this is usually handled in PHP?  Do you have to write 'if statements' to handle it? 

 

Thanks for any help guys!

[Bendude14]

try this

 

if(isset($_POST["postedvariable"]))
{
    $variable = $_POST["postedvariable"];
}

[RynMan]

try this

 

if(isset($_POST["postedvariable"]))
{
    $variable = $_POST["postedvariable"];
}

 

Thanks Ben.  But what now happens if the value of $_POST["postedvariable"] is null?

[Bendude14]

well isset() checks if the variable was ever set.

 

if $_POST["postedvariable"] is empty you can check this also like so

if(empty($_POST["postedvariable"]))
{
    //more code
}

 

if $_POST["postedvariable"] actually contains the value null you will have to check for this seperatly like so

 

if($_POST["postedvariable"] == null)
{
    //more code
}

 

with these examples you should be able to put them together and take action accordingly...

 

Ben

[RynMan]

well isset() checks if the variable was ever set.

 

if $_POST["postedvariable"] is empty you can check this also like so

if(empty($_POST["postedvariable"]))
{
    //more code
}

 

if $_POST["postedvariable"] actually contains the value null you will have to check for this seperatly like so

 

if($_POST["postedvariable"] == null)
{
    //more code
}

 

with these examples you should be able to put them together and take action accordingly...

 

Ben

 

I see.  I've elected to try this...

 

if(empty($Gender)) 
$Gender == null;
else
$Gender = $_POST["Gender"];	

 

However it still doesn't like it because $Gender has nothing assigned to it.  Instead of null I also tried '' however that didn't work either.  What can I put there that both satisfy the PHP (the variable is defined) and the mySQL (something to insert)?

[Bendude14]

do you have a constraint on you table in mysql that does now allow null as a value? because otherwise that should work...

 

If you check and their are no constraints on the column post your query here...

 

When you say it doesn't work, what errors are you getting?

[RynMan]

do you have a constraint on you table in mysql that does now allow null as a value? because otherwise that should work...

 

If you check and their are no constraints on the column post your query here...

 

When you say it doesn't work, what errors are you getting?

 

I'm using PHPMyAdmin and in my table structure, almost all of my fields have "No" under the "NULL" column.  I'm guessing I need to change them to yes. 

[Daniel0]

The $_POST array cannot contain null values unless you put them there manually. Even an empty field submitted via a form won't be null, but rather an empty string. Those two things aren't the same.

[Bendude14]

yes you need to change them to allow null as a value.

 

As daniel said for having empty strings you are checking against that already with this code.

 

if(empty($Gender))
   $Gender == null;
else
   $Gender = $_POST["Gender"];