The lazy loading was done correctly. The function _connect is a private function, therefore, may only be called by the class itself. The class only calls the _connect function in case you are doing a query. In addition to that, the query function will look if the connection has already been made.

I am a bit confused with a scenario. I got to select 42 columns out of 52 from a table. Columns include primary key columns as well. What will be better? selecting 42 columns or using select *? What is the limit till the time Select performs better than Select * ?

private function _connect() {
if ($this->_connection = mysql_connect()) {
$this->_connected = true;
}
}

In every check you connect to the database. It should be something like:

private function _connect() {
if (is_null($this->_connection)) {
$this->_connection = mysql_connect();
$this->_connected = true;
}
}

*for clarity I skipped the statement to check or mysql is actualy connected.

In this example you see that everytime you try to “_connect” php doesn’t connect to the SQL server if a connection is already set.