users and posts database issue - php

Question

Is it true that after a user signs up, a sql table is create for him to store his posts ?
I make it similar in mysql after the man insert him into my page. The database is the same name with but the table name is made when he log in first time.
class Users
{
var $username="root";
var $password="pass";
var $database="InsertIntoStackOverflow";
var $table_name="";
public function Users($username)
{
$table_name=$username."_tb";
echo $table_name."<br/>";
mysql_connect(localhost,$username, $password) or die("unable to connect to database ".mysql_error());
echo $database."<br/>";
mysql_selectdb($database) or die("unable to select db ".mysql_error());
$query="CREATE TABLE ".$table_name." (id tinyint(4) NOT NULL AUTO_INCREMENT, title VARCHAR(128) NOT NULL, date_post VARCHAR(100), date_edit VARCHAR(100), post_content TEXT NOT NULL)";
mysql_query($query) or die("Unable to create table. ".mysql_error());
}
}
But it display only table_name and an error, the database name not display. Error is NO DATABASE IS SELECTED/
EDIT
This class is call after he sign up
I also have a function postApost but when I do
ob_start();
session_start();
require("Users_DB.php");
$name=$_SESSION['user'];
echo 'Welcome '.$name;
$username=new UserDB($name);
there is no table created

Answer 1

Two variables with same name $username. Use $this for accessing variable of class. Missing quote(") with localhost - it must be string type parameter. and this code can't create table on Database because you use AUTO_INCREMENT on your code but forgot to mention that as a PRIMARY KEY. I think the following code help you a lot.
class Users
{
var $username="root";
var $password="pass";
var $database="InsertIntoStackOverflow";
var $table_name="";
function __construct($user_name)
{
$this->table_name=$user_name."_tb";
echo $this->table_name."<br/>";
mysql_connect("localhost",$this->username, $this->password) or die("unable to connect to database ".mysql_error());
echo $this->database."<br/>";
mysql_selectdb($this->database) or die("unable to select db ".mysql_error());
$query="CREATE TABLE ".$this->table_name." (id tinyint(4) NOT NULL AUTO_INCREMENT, title VARCHAR(128) NOT NULL, date_post VARCHAR(100), date_edit VARCHAR(100), post_content TEXT NOT NULL, PRIMARY KEY (id))";
mysql_query($query) or die("Unable to create table. ".mysql_error());
}
}
And you can use this class by the following way :
$clsName = new Users('username');

Answer 2

Create one table:
CREATE TABLE Posts (
id TINYINT(4) NOT NULL AUTO_INCREMENT,
user VARCHAR(20) NOT NULL,
title VARCHAR(128) NOT NULL,
date_post DATETIME,
date_edit DATETIME,
post_content TEXT NOT NULL
)
Inserting new posts:
$insert = "
INSERT INTO Posts (
user,
title,
date_post,
date_edit,
post_content
) VALUES (
'$username',
'$title',
NOW(),
NOW(),
'$post_content'
)
";
Updating is simple:
$update = "
UPDATE Posts SET
title = '$title',
post_content = '$post_content',
date_edit = NOW()
WHERE id = '$postid';
";
Get all posts for user:
$posts = "
SELECT title, date_post, date_edit, post_content
FROM Posts
WHERE user = '$username'
ORDER BY date_post
";