Can anyone what this handle means?

idnoble

Hello all,
I'm going through some PHP scripts and I can't figure out some stuffs in there, the script is used to update a blob field in a mysql table.

Below are the Mysql table and the PHP scripts:

DROP TABLE Blobtab;
CREATE TABLE Blobtab
( blob_id INTEGER AUTO_INCREMENT PRIMARY KEY,
blob_data LONGBLOB,
fdescription CHARACTER VARYING(50),
filename CHARACTER(25),
filesize CHARACTER(25),
filetype CHARACTER(25)
);

the PHP script

<?php
$session = mysql_connect("localhost", "", "");
mysql_select_db("ee3103");
$fd = fopen($form_data, "rb");
$data = addslashes(fread($fd, filesize($form_data)));
$query = "INSERT INTO Blobtab(blob_data, fdescription, filename, filesize, filetype) " .
"VALUES ('$data', '$form_description', '$form_data_name', '$form_data_size', '$form_data_type')";
$result = mysql_query($query);
if ( !$result )
{
echo ( "Error performing INSERT: " . mysql_error() . "" );
}
else
{
$blobid = mysql_insert_id();
print "This file has the following BLOB ID: $blobid";
}
fclose($fd);
mysql_close($session);
?>

I am confused about the $fd and what its for, can anyone help me out here

Buddha443556

When you open a file your give a unique identifier (in this case $fd) for that open file. In all sequential operations on that file, such as reading or writing, you use the unique identifier to indecate what open file to work with. You can have more than one open file.

Hope that helps.

idnoble

So am I to choose just any name for my unique udentifier and add the $ sign infront? or are there some conventions I need to follow before I chose a unique identifier?

Buddha443556

Originally posted by idnoble
So am I to choose just any name for my unique udentifier and add the $ sign infront? or are there some conventions I need to follow before I chose a unique identifier?

The unique indentifier is created by the operating system. $fd is a variable storing the unique indentifier , you can store it under any variable name you want. The examples in the PHP manual seem to perfer $handle. The $fd in your example probably stands for 'file descriptor' but whatever you call name it should be something that makes it easier to read your code.

Basically all coding standards (except those implemented by the DOD 😃 ) try to make code more readable. Whatever naming convention you choose make sure you apply it consistantly.