PHP upload to database

I am trying to upload things to a database. I went through a few tutorials and none of them worked. I want to upload files such as images and text documents (including PowerPoint presentations) to the database.

This is my form

<form action="upload.php" method="post" enctype="multipart/form-data" name="uploadform">
    <input type="hidden" name="MAX_FILE_SIZE" value="350000">
    <input name="picture" type="file" id="picture" size="50">
    <input name="upload" type="submit" id="upload" value="Upload Picture!">
</form>

This is upload.php

<?php
// if something was posted, start the process...
if(isset($_POST['upload']))
{
    // define the posted file into variables
    $name = $_FILES['picture']['name'];
    $tmp_name = $_FILES['picture']['tmp_name'];
    $type = $_FILES['picture']['type'];
    $size = $_FILES['picture']['size'];

    // get the width & height of the file (we don't need the other stuff)
    list($width, $height, $typeb, $attr) = getimagesize($tmp_name);

    // if width is over 600 px or height is over 500 px, kill it    
    if($width>600 || $height>500)
    {
        echo $name . "'s dimensions exceed the 600x500 pixel limit.";
        echo '<a href="form.html">Click here</a> to try again.';
        die();
    }

    // if the mime type is anything other than what we specify below, kill it    
    if(!($type=='image/jpeg' || $type=='image/png' || $type=='image/gif')) 
    {
        echo $type .  " is not an acceptable format.";
        echo '<a href="form.html">Click here</a> to try again.' ;
        die();
    }

    // if the file size is larger than 350 KB, kill it
    if($size>'350000') {
        echo $name . " is over 350KB. Please make it smaller.";
        echo '<a href="form.html">Click here</a> to try again.' ;
        die();
    } 

    // if your server has magic quotes turned off, add slashes manually
    if(!get_magic_quotes_gpc()){
        $name = addslashes($name);
    }

    // open up the file and extract the data/content from it
    $extract = fopen($tmp_name, 'r');
    $content = fread($extract, $size);
    $content = addslashes($content);
    fclose($extract);  

    // connect to the database
    include "inc/db.inc.php";

    // the query that will add this to the database
    $addfile = "INSERT INTO files (name, size, type, content ) ".
        "VALUES ('$name', '$size', '$type', '$content')";

    mysql_query($addfile) or die(mysql_error());

    // get the last inserted ID if we're going to display this image next
    $inserted_fid = mysql_insert_id();

    mysql_close(); 

    echo "Successfully uploaded your picture!";

    // we still have to close the original IF statement. If there was nothing posted, kill the page.
}
else{
    die("No uploaded file present");
}
?>  

I know there is restriction on type -> if(!($type=='image/jpeg' || $type=='image/png' || $type=='image/gif')) on this. When I upload small photos, the error I am getting is "No database selected".

The database is configured correctly as other things that I have are able to connect to it.