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!

since nothing was entered, nothing is posted, and the query fails since there is no value.

It depends of your DB.
If the field is created with a NOT NULL constraint, then yes, it's probably your problem.

You must understand that you have 2 systems now that talk together.
You have PHP, that process the requests, and you have the DB, which execute requests sent by PHP and return a feedback.

Your error might be in the PHP layer, but it can be that PHP is just relaying back an error that occured in the DB layer.

Read (and post here) the error message returned by PHP, it will change depending where the problem occured, and we'll be able to help you further.
Post the structure of the sql table you want to insert into too. It will help us.

yup as tripy said,

you could also set a default value for that column

You also want to be sure to quote your db field value data so if it's an empty string, it will still validate as proper sql statement rather than cause an sql error.

Ex:
Do this: VALUES('$var1', '$var2') instead of this: VALUES($var1, $var2)

Originally Posted by mgraphic

You also want to be sure to quote your db field value data so if it's an empty string, it will still validate as proper sql statement rather than cause an sql error.

Ex:
Do this: VALUES('$var1', '$var2') instead of this: VALUES($var1, $var2)

not to hijack thread but I've always wondered about that

"UPDATE $table SET $column='$var1' WHERE $column2='$var2'";

how come table, column, and column2 doesn't have to be in '' but $var1, and 2 has to be?

because $table, $column, $column2 are Variables

and '$var1' , '$var2' are Values

---

one uses Variables to access the Values, not Values to access the Variables.


if you put the Variables into single quotes (''), you would get a parse error. Why is this?

because PHP will not be able to reference the Variables, it will not be able to return the Values of those Variables.

Originally Posted by orionoreo

not to hijack thread but I've always wondered about that

"UPDATE $table SET $column='$var1' WHERE $column2='$var2'";

how come table, column, and column2 doesn't have to be in '' but $var1, and 2 has to be?

Like Lashtal said, $var1 and $var2 are values. Things like table and column are references to a defined instance. It is common practice to use a non-breaking name for these types of instances such as field_name and column_name, however you can rather use a tic mark (`) to enclose these types, even with a space such as `Table Name` and `Column Name`

understood... thanks!