What is the difference between $var and $$var?
$day='monday'; $$day='first day of week'; echo $monday; //outputs 'first day of week'
What is .htaccess in PHP?
.htaccess is a configuration file for use on web servers running the Apache Web Server software. When a .htaccess file is placed in a directory which is in turn ‘loaded via the Apache Web Server’, then the .htaccess file is detected and executed by the Apache Web Server software.
What is Nginx and what is it used for?
NGINX (Pronounced as Engine-X) is an open source, lightweight, high-performance web server or proxy server. Nginx used as reverse proxy server for HTTP, HTTPS, SMTP, IMAP, POP3 protocols, on the other hand, it is also used for servers load balancing and HTTP Cache
Set the PHP default timezone :
echo date('d-m-Y H:i:s'); //Returns IST
Default Mysql Port No, Host and Protocol :
mysql –port = 3306 –host=127.0.0.1
mysql --port = 3306 --protocol=TCP
Index in SQL :
Indexes allow the database application to find data fast;
without reading the whole table.
An index can be created in a table to find data more quickly and efficiently.
The users cannot see the indexes, they are just used to speed up searches/queries.
Note: Updating a table with indexes takes more time than updating a table without
(because the indexes also need an update). So you should only create indexes on columns (and tables)
that will be frequently searched against.
SQL CREATE INDEX Syntax
Creates an index on a table. Duplicate values are allowed:
ON table_name (column_name)
Virtual Hosting :
Ex :1 Virtual hosting
is a method for hosting multiple domain names (with separate handling of each name) on a single server (or pool of servers). This allows one server to share its resources, such as memory and processor cycles, without requiring all services provided to use the same host name. Ex : 2 The term Virtual Host refers to the practice of running more than one web site (such as
company2.example.com) on a single machine. Virtual hosts can be "IP-based", meaning that you have a different IP address for every web site, or "name-based
", meaning that you have multiple names running on each IP address. The fact that they are running on the same physical server is not apparent to the end user.