File upload and Download in Php

$connectionString = mysql_connect('host', 'MySQL username', 'MySQL Password');//Connect to the MySQL database
$selectDatabase = mysql_selectdb('MySQL Database Name', $connectionString);//Connect to your database

//To get something to the database
$tableGetQuery = mysql_query("SELECT * FROM `table` WHERE `field` = 'value'");//Query the database table
$tableGetArray = mysql_fetch_array($tableGetQuery);//Split the table into individual elements
$tableFieldValue = $tableGetArray['field_name'];//Get the value of the table cell
//To add to the table
$tableAddQuery = mysql_query = "INSERT INTO `table` (`field_name`, `other_field_name`) VALUES ('value1', 'value2')";

//To upload

if($_POST['submit'])//Form submit - where 'file' is the file upload HTML element
{
	if($_FILES["file"]["error"] > 0)//Check if there is an error
	{
		$msg = "Error: ".$_FILES["file"]["error"];
	}
	else
	{
	    if(file_exists("upload/".$_FILES["file"]["name"]))//Checks if file exists
            {
		$msg = "The file already exists!";
            }
	    else
	    {
		move_uploaded_file($_FILES["file"]["tmp_name"], "upload/". $_FILES["file"]["name"]);//Moves the uploaded file from the temporary directory ('tmp_name') to the 'upload/' directory
	    }
	}
}