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Validate Input Fields

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Join Date: Oct 2005

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humbug

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Re: Validate Input Fields

#11

Nov 2nd, 2008

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Originally Posted by antwan1986

Perhaps I've misunderstood the question, and the two previous posters used regular expressions but I would normally test a date with something like the following:
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PHP Syntax (Toggle Plain Text)
function is_date($value) {
  // If the value of the field is empty, immediately return false.
  if (empty($value)) { return FALSE; }
 
  // Attach the exploded values to variables.
  list($day, $month, $year) = explode("/", $value);
 
  // Check those variables in the checkdate function. If it's valid, the function returns true.
  return checkdate($month, $day, $year);
}
function is_date($value) { // If the value of the field is empty, immediately return false. if (empty($value)) { return FALSE; } // Attach the exploded values to variables. list($day, $month, $year) = explode("/", $value); // Check those variables in the checkdate function. If it's valid, the function returns true. return checkdate($month, $day, $year); }

This is a great method for the date. If you wanted to you could even return "$year - $month - $day"; if it is a valid date or FALSE if it isn't seeing as you already have the variables set.

As for the time, I would probably take the input as a string and use one of the regular expression checks above to see if it consists of 4 numbers, then typecast it to an integer and check if ($time_num >= 900 && $time_num <= 1700) { echo "time is valid"; }

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jackakos

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Re: Validate Input Fields

#12

Nov 5th, 2008

Great Stuff!

Your postings have giving me much understanding of most issues.

start_time is a varchar data type, is it possible to perform an addition on this variable?

Supposing $start_time has a value 1100 because I am using 24 hour format can I add a value to it?

ie. $start_time = $start_time + 100;

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Join Date: Oct 2005

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humbug

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Re: Validate Input Fields

#13

Nov 6th, 2008

In php, if you try to perform an operation on $start_time (assuming that it is a variable in the script containing a string) it will be used as an integer. It works fine if the string is something like "1234". $start_time will then be converted to an integer variable (because it is on the left of the "=").

If there is a column in a mysql table that is named "start_time" and is a varchar datatype and you do something like $start_time = $row['start_time'] (where $row contains a row of a result from a query) then $start_time will be a string.

If you are writing a query to submit data to the mysql database and you can do something like

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$query = "INSERT INTO table (`start_time`, `finish_time`) VALUES ( " . $start_time . ", " . $finish_time . ")";
//or
$query = "INSERT INTO table (`start_time`, `finish_time`) VALUES ( '" . $start_time . "', '" . $finish_time . "')";
$query = "INSERT INTO table (`start_time`, `finish_time`) VALUES ( " . $start_time . ", " . $finish_time . ")";
//or
$query = "INSERT INTO table (`start_time`, `finish_time`) VALUES ( '" . $start_time . "', '" . $finish_time . "')";

With the single quotes ('), the mysql treats whatever is in them as a string no matter what. When you do $string = "$int"; or $string = "number is " . $int; , $int is used as a string. So when you are creating the query it doesn't matter what type $start_time is. Without the single quotes I think SQL will assume it's whatever type it needs to be. (mysql converts it to the right data type anyway so there's usually no problem). Just be careful doing "... WHERE culumn_name=$string" instead of "... WHERE culumn_name='$string'" because other wise only the first word of $string will be used.

This changing types is called "typecasting" if you want to research it more or anything like that.