Choose meaningful variable names and remember they're case-sensitive.
Use comments to remind you what your script does.
Remember that numbers don't require quotes, but strings (text) do.
You can use single or double quotes, but the outer pair must match.
Use a backslash to escape quotes of the same type inside a string.
To store related items together, use an array.
Use conditional statements, such as if and if... else, for decision making.
Simplify repetitive tasks with loops.
Use functions to perform preset tasks.
Display PHP output with echo or print.
Inspect the content of arrays with print_r().
With most error messages, work backward from the position indicated.
Keep smiling—and remember that PHP is not difficult.
Thursday, May 17, 2007
Tuesday, May 15, 2007
THE H1B VISA PROCESS : USA UK CANADA Australia Jobs Search Engine
THE H1B VISA PROCESS :-
to obtain an H1B visa, an applicant must 'first' find an H1B job with an H1B visa employer company in the USA; commonly known as your 'H1B sponsor'.
Your H1B sponsor then applies for / files your H1B visa application. Individuals can NOT sponsor or apply for their own H1B visa - ONLY your new employer (sponsor) can.
An H1B visa is typically valid for up to six (6) years and entitles your spouse (husband/wife) and children to accompany you and 'live' in America.
One of the main advantages of the H1B visa (US work permit) is that it is a 'dual intent' visa which means that you can apply for a Green Card (Legal Permanent Residency).
To obtain an H1B visa to work in the USA....
* the 1st step is that you Must find an H1B Job with an H1B sponsor company.
* Individuals can Not sponsor/apply for your own H1B visa - only your new employer can.
H1B Visa Global Jobs Consultant Search Global jobs online UK USA CANADA and Australia
H-1B visa
http://globaljobsonline.blogspot.comThe US H1B visa is a non-immigrant visa, which allows a US company to employ a foreign individual for up to six years. As applying for a non-immigration visa is generally quicker than applying for a US Green Card, staff required on long-term assignment in the US are often initially brought in using a non-immigrant visa such as the H1B visa.
Individuals can not apply for an H1B visa to allow them to work in the US. The employer must petition for entry of the employee. H1B visas are subject to annual numerical limits.
US employers may begin applying for the H-1B visa six months before the actual start date of the visa. Since the beginning of the FY 2007 is October 1, 2006, employers can apply as soon as April 1, 2006 for the FY 2007 cap, but the beneficiary cannot start work until October 1st.
The H1B visa is designed to be used for staff in "speciality occupations", that is those occupations which require a high degree of specialized knowledge. Generally at least the equivalent of a job-relevant 4-year US Bachelor's degree is required (this requirement can usually be met by having a 3-year degree and 3 years' relevant post-graduate experience). However, professionals such as lawyers, doctors, accountants and others must be licensed to practice in the state of intended employment – e.g. a lawyer must generally have passed the relevant state bar exam.
Non-graduates may be employed on an H1B visa where they can claim to be 'graduate equivalent' by virtue of twelve or more years' experience in the occupation.
Positions that are not "speciality occupations", or for which the candidate lacks the qualifications/experience for an H1B visa, may be filled using an H-2B visa. The disadvantage of the H-2B visa is that it requires 'labor certification' - an expensive and time consuming process that involves extensive advertising of the position, and satisfying the authorities that there are no US workers available to do the job. Also, H-2B visas are initially granted only for one year, extendable in one year increments to a maximum of 3 years. As each extension requires a new Labor Certification, it unsurprising that, of the annual quota of 66,000 H-2B visas, only a few thousand are ever issued.
New H1B legislation requires certain employers, called 'H1B dependent employers' to advertise positions in the USA before petitioning to employ H1B workers for those positions. H1B dependent employers are defined as those having more than 15% of their employees in H1B status (for firms with over 50 employees – small firms are allowed a higher percentage of H1B employees before becoming 'dependent'). In addition all new H1B petitions and 1st extensions of H1B's now require a fee (in addition to the usual filing fees) of US$1,000 to be paid, which will be used to fund a training programme for resident US workers.
The initial visa may be granted for up to three years. It may then be extended, in the first instance for up to two further years, and eventually for one further year, to a maximum of six years. Those wishing to remain in the US for more than six years may, while still in the US on an H1B visa, apply for permanent residence (the "green card"): if such employees do not gain permanent residence, when the six year period runs out, they must live outside the US for at least one year before an application is made for them to enter on an H or an L visa.
Once a company has brought an employee to the US on an H1B visa, should the company dismiss that employee before the expiry of the visa, the company is liable for any reasonable costs that the employee incurs in moving him/herself, his/her effects, back to his/her last foreign residence. This provision covers only dismissal, it is not relevant when an employee chooses to resign.
Monday, May 14, 2007
Polymorphism PHP Mysql
Polymorphism
The database wrappers developed in this chapter are pretty generic. In fact, if you look at the other database extensions built in to PHP, you see the same basic functionality over and over againconnecting to a database, preparing queries, executing queries, and fetching back the results. If you wanted to, you could write a similar DB_Pgsql or DB_Oracle class that wraps the PostgreSQL or Oracle libraries, and you would have basically the same methods in it.
In fact, although having basically the same methods does not buy you anything, having identically named methods to perform the same sorts of tasks is important. It allows for polymorphism, which is the ability to transparently replace one object with another if their access APIs are the same.
In practical terms, polymorphism means that you can write functions like this:
function show_entry($entry_id, $dbh)
{
$query = "SELECT * FROM Entries WHERE entry_id = :1";
$stmt = $dbh->prepare($query)->execute($entry_id);
$entry = $stmt->fetch_row();
// display entry
}
This function not only works if $dbh is a DB_Mysql object, but it works fine as long as $dbh implements a prepare() method and that method returns an object that implements the execute() and fetch_assoc() methods.
To avoid passing a database object into every function called, you can use the concept of delegation. Delegation is an OO pattern whereby an object has as an attribute another object that it uses to perform certain tasks.
The database wrapper libraries are a perfect example of a class that is often delegated to. In a common application, many classes need to perform database operations. The classes have two options:
-
You can implement all their database calls natively. This is silly. It makes all the work you've done in putting together a database wrapper pointless.
-
You can use the database wrapper API but instantiate objects on-the-fly. Here is an example that uses this option:
class Weblog {
public function show_entry($entry_id)
{
$query = "SELECT * FROM Entries WHERE entry_id = :1";
$dbh = new Mysql_Weblog();
$stmt = $dbh->prepare($query)->execute($entry_id);
$entry = $stmt->fetch_row();
// display entry
}
}
On the surface, instantiating database connection objects on-the-fly seems like a fine idea; you are using the wrapper library, so all is good. The problem is that if you need to switch the database this class uses, you need to go through and change every function in which a connection is made.
-
You implement delegation by having Weblog contain a database wrapper object as an attribute of the class. When an instance of the class is instantiated, it creates a database wrapper object that it will use for all input/output (I/O). Here is a re-implementation of Weblog that uses this technique:
class Weblog {
protected $dbh;
public function setDB($dbh)
{
$this->dbh = $dbh;
}
public function show_entry($entry_id)
{
$query = "SELECT * FROM Entries WHERE entry_id = :1";
$stmt = $this->dbh->prepare($query)->execute($entry_id);
$entry = $stmt->fetch_row();
// display entry
}
}
Now you can set the database for your object, as follows:
$blog = new Weblog;
$dbh = new Mysql_Weblog;
$blog->setDB($dbh);
Of course, you can also opt to use a Template pattern instead to set your database delegate:
class Weblog_Std extends Weblog {
protected $dbh;
public function _ _construct()
{
$this->dbh = new Mysql_Weblog;
}
}
$blog = new Weblog_Std;
Delegation is useful any time you need to perform a complex service or a service that is likely to vary inside a class. Another place that delegation is commonly used is in classes that need to generate output. If the output might be rendered in a number of possible ways (for example, HTML, RSS [which stands for Rich Site Summary or Really Simple Syndication, depending on who you ask], or plain text), it might make sense to register a delegate capable of generating the output that you want.
The Template Pattern - PHP Mysql Class
The Template Pattern
The Template pattern describes a class that modifies the logic of a subclass to make it complete.
You can use the Template pattern to hide all the database-specific connection parameters in the previous classes from yourself. To use the class from the preceding section, you need to constantly specify the connection parameters:
<?php
require_once 'DB.inc';
define('DB_MYSQL_PROD_USER', 'test');
define('DB_MYSQL_PROD_PASS', 'test');
define('DB_MYSQL_PROD_DBHOST', 'localhost');
define('DB_MYSQL_PROD_DBNAME', 'test');
$dbh = new DB::Mysql(DB_MYSQL_PROD_USER, DB_MYSQL_PROD_PASS,
DB_MYSQL_PROD_DBHOST, DB_MYSQL_PROD_DBNAME);
$stmt = $dbh->execute("SELECT now()");
print_r($stmt->fetch_row());
?>
To avoid having to constantly specify your connection parameters, you can subclass DB_Mysql and hard-code the connection parameters for the test database:
class DB_Mysql_Test extends DB_Mysql {
protected $user = "testuser";
protected $pass = "testpass";
protected $dbhost = "localhost";
protected $dbname = "test";
public function _ _construct() { }
}
Similarly, you can do the same thing for the production instance:
class DB_Mysql_Prod extends DB_Mysql {
protected $user = "produser";
protected $pass = "prodpass";
protected $dbhost = "prod.db.example.com ";
protected $dbname = "prod";
public function _ _construct() { }
}
PHP Mysql Class
The Adaptor Pattern
The Adaptor pattern is used to provide access to an object via a specific interface. In a purely OO language, the Adaptor pattern specifically addresses providing an alternative API to an object; but in PHP we most often see this pattern as providing an alternative interface to a set of procedural routines.
Providing the ability to interface with a class via a specific API can be helpful for two main reasons:
-
If multiple classes providing similar services implement the same API, you can switch between them at runtime. This is known as polymorphism. This is derived from Greek: Poly means "many," and morph means "form."
-
A predefined framework for acting on a set of objects may be difficult to change. When incorporating a third-party class that does not comply with the API used by the framework, it is often easiest to use an Adaptor to provide access via the expected API.
The most common use of adaptors in PHP is not for providing an alternative interface to one class via another (because there is a limited amount of commercial PHP code, and open code can have its interface changed directly). PHP has its roots in being a procedural language; therefore, most of the built-in PHP functions are procedural in nature. When functions need to be accessed sequentially (for example, when you're making a database query, you need to use mysql_pconnect(), mysql_select_db(), mysql_query(), and mysql_fetch()), a resource is commonly used to hold the connection data, and you pass that into all your functions. Wrapping this entire process in a class can help hide much of the repetitive work and error handling that need to be done.
The idea is to wrap an object interface around the two principal MySQL extension resources: the connection resource and the result resource. The goal is not to write a true abstraction but to simply provide enough wrapper code that you can access all the MySQL extension functions in an OO way and add a bit of additional convenience. Here is a first attempt at such a wrapper class:
class DB_Mysql {
protected $user;
protected $pass;
protected $dbhost;
protected $dbname;
protected $dbh; // Database connection handle
public function _ _construct($user, $pass, $dbhost, $dbname) {
$this->user = $user;
$this->pass = $pass;
$this->dbhost = $dbhost;
$this->dbname = $dbname;
}
protected function connect() {
$this->dbh = mysql_pconnect($this->dbhost, $this->user, $this->pass);
if(!is_resource($this->dbh)) {
throw new Exception;
}
if(!mysql_select_db($this->dbname, $this->dbh)) {
throw new Exception;
}
}
public function execute($query) {
if(!$this->dbh) {
$this->connect();
}
$ret = mysql_query($query, $this->dbh);
if(!$ret) {
throw new Exception;
}
else if(!is_resource($ret)) {
return TRUE;
} else {
$stmt = new DB_MysqlStatement($this->dbh, $query);
$stmt->result = $ret;
return $stmt;
}
}
}
To use this interface, you just create a new DB_Mysql object and instantiate it with the login credentials for the MySQL database you are logging in to (username, password, hostname, and database name):
$dbh = new DB_Mysql("testuser", "testpass", "localhost", "testdb");
$query = "SELECT * FROM users WHERE name = '".mysql_escape_string($name)."'";
$stmt = $dbh->execute($query);
This code returns a DB_MysqlStatement object, which is a wrapper you implement around the MySQL return value resource:
class DB_MysqlStatement {
protected $result;
public $query;
protected $dbh;
public function _ _construct($dbh, $query) {
$this->query = $query;
$this->dbh = $dbh;
if(!is_resource($dbh)) {
throw new Exception("Not a valid database connection");
}
}
public function fetch_row() {
if(!$this->result) {
throw new Exception("Query not executed");
}
return mysql_fetch_row($this->result);
}
public function fetch_assoc() {
return mysql_fetch_assoc($this->result);
}
public function fetchall_assoc() {
$retval = array();
while($row = $this->fetch_assoc()) {
$retval[] = $row;
}
return $retval;
}
}
To then extract rows from the query as you would by using mysql_fetch_assoc(), you can use this:
while($row = $stmt->fetch_assoc()) {
// process row
}
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