PHP Interview Questions for Freshers 02

What is the difference between mysql_fetch_object and mysql_fetch_array?

MySQL fetch object will collect first single matching record where mysql_fetch_array will collect all matching records from the table in an array.
What is the difference between $message and $$message?

They are both variables. But $message is a variable with a fixed name. $$message is a variable who’s name is stored in $message. For example, if $message contains “var”, $$message is the same as $var.
What are the differences between require and include, include_once?

File will not be included more than once. If we want to include a file once only and further calling of the file will be ignored then we have to use the PHP function include_once().
This will prevent problems with function redefinitions, variable value reassignments, etc.

What are the different tables present in mysql?

Total 5 types of tables we can create

1. MyISAM

2. Heap

3. Merge

4. InnoDB

5. ISAM

6. BDB

MyISAM is the default storage engine as of MySQL 3.23.

How can I execute a php script using command line?

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.