PHP questions

Question : What are the differences between require and include, include_once and require_once?

Answer :

The include() statement includes and evaluates the specified file.The documentation below also applies to require(). The two constructs are identical in every way except how they handle
failure. include() produces a Warning while require() results in a Fatal Error. In other words, use
require() if you want a missing file to halt processing of the page. include() does not behave this way, the script will continue regardless. The include_once() statement includes and evaluates the
specified file during the execution of the script. This is a behavior similar to the include() statement, with the only difference being that if the code from a file has already been included, it will not be
included again. As the name suggests, it will be included just once.include_once() should be used in cases where the same file might be included and evaluated more than once during a particular execution of a script, and you want to be sure that it is included exactly once to avoid problems with function redefinitions, variable value reassignments, etc. require_once() should be used in cases where the same file might be included and evaluated more than once during a particular execution of a script, and you want to be sure that it is included exactly once to avoid problems with function
redefinitions, variable value reassignments, etc.

Question : Can we use include (”abc.PHP”) two times in a PHP page “makeit.PHP”?

Answer : Yes we can use include() more than one time in any page though it is not a very good practice.

Question : What are the different tables present in MySQL, which type of table is generated when we are creating a table in the following syntax:
create table employee (eno int(2),ename varchar(10)) ?

Answer : Total 5 types of tables we can create
1. MyISAM
2. Heap
3. Merge
4. INNO DB
5. ISAM
MyISAM is the default storage engine as of MySQL 3.23 and as a result if
we do not specify the table name explicitly it will be assigned to the
default engine.

Question : Functions in IMAP, POP3 AND LDAP?

Answer : You can find these specific information in PHP Manual.

Question : How can I execute a PHP script using command line?

Answer : As of version 4.3.0, PHP supports a new SAPI type (Server Application Programming Interface) named CLI which means Command Line Interface. Just run the PHP CLI (Command Line Interface) program and provide the PHP script file name as the command line argument. For example, “php myScript.php”, assuming “php” is the command to invoke the CLI program.
Be aware that if your PHP script was written for the Web CGI interface, it may not execute properly in command line environment.

Question : Suppose your Zend engine supports the mode . Then how can you
configure your PHP Zend engine to support mode ?

Answer : In php.ini file:
set
short_open_tag=on
to make PHP support

Question : Shopping cart online validation i.e. how can we configure Paypal,
etc.?

Answer : We can find the detail documentation about different paypal integration process at the following site PayPal PHP
SDK : http://www.paypaldev.org/

Question : What is meant by nl2br()?

Answer : Inserts HTML line breaks
(
)
before all newlines in a string string nl2br (string); Returns string with ” inserted before all newlines.
For example: echo nl2br(”god blessn you”) will output “god bless
you” to your browser.