Basics of PHP

Started by Kalyan, Dec 06, 2008, 08:38 AM

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Kalyan

Basics of PHP

Who is the father of PHP and what is the current version of PHP and MYSQL?

Rasmus Lerdorf.
PHP 5.1. Beta
MySQL 5.0

In how many ways we can retrieve data in the result set of MYSQL using PHP?

mysql_fetch_array - Fetch a result row as an associative array, a numeric array, or both
mysql_fetch_assoc - Fetch a result row as an associative array
mysql_fetch_object - Fetch a result row as an object
mysql_fetch_row â€"- Get a result row as an enumerated array

What are the functions for IMAP?

imap_body - Read the message body
imap_check - Check current mailbox
imap_delete - Mark a message for deletion from current mailbox
imap_mail - Send an email message

What are encryption functions in PHP?

CRYPT()
MD5()

What is the difference between htmlentities() and htmlspecialchars()?

htmlspecialchars() - Convert some special characters to HTML entities (Only the most widely used)
htmlentities() - Convert ALL special characters to HTML entities

What is the functionality of the function htmlentities?

htmlentities() - Convert all applicable characters to HTML entities
This function is identical to htmlspecialchars() in all ways, except with htmlentities(), all characters which have HTML character entity equivalents are translated into these entities.

How can we get the properties (size, type, width, height) of an image using php image functions?

To know the image size use getimagesize() function
To know the image width use imagesx() function
To know the image height use imagesy() function

How can we increase the execution time of a php script?

By the use of void set_time_limit(int seconds)
Set the number of seconds a script is allowed to run. If this is reached, the script returns a fatal error. The default limit is 30 seconds or, if it exists, the max_execution_time value defined in the php.ini. If seconds is set to zero, no time limit is imposed.

When called, set_time_limit() restarts the timeout counter from zero. In other words, if the timeout is the default 30 seconds, and 25 seconds into script execution a call such as set_time_limit(20) is made, the script will run for a total of 45 seconds before timing out.

HOW CAN WE TAKE A BACKUP OF A MYSQL TABLE AND HOW CAN WE RESTORE IT?
Answer 1:
Create a full backup of your database: shell> mysqldump tab=/path/to/some/dir opt db_name
Or: shell> mysqlhotcopy db_name /path/to/some/dir
The full backup file is just a set of SQL statements, so restoring it is very easy:

shell> mysql "."Executed";

Answer 2:
To backup: BACKUP TABLE tbl_name TO /path/to/backup/directory
' To restore: RESTORE TABLE tbl_name FROM /path/to/backup/directory

mysqldump: Dumping Table Structure and Data

Utility to dump a database or a collection of database for backup or for transferring the data to another SQL server (not necessarily a MySQL server). The dump will contain SQL statements to create the table and/or populate the table.
-t, no-create-info
Don't write table creation information (the CREATE TABLE statement).
-d, no-data
Don't write any row information for the table. This is very useful if you just want to get a dump of the structure for a table!

How to set cookies?

setcookie('variable','value','time')
;
variable - name of the cookie variable
value - value of the cookie variable
time - expiry time
Example: setcookie('Test',$i,time()+3600);

Test - cookie variable name
$i - value of the variable 'Test'
time()+3600 - denotes that the cookie will expire after an one hour