for is expressed as follows:
for (expr1; expr2; expr3)
statement
The first expression is executed once at the beginning. In each iteration, expr2 is evaluated. If it is TRUE, the loop continues, and the statements inside for are executed. If it evaluates to FALSE, the execution of the loop ends. expr3 is tested at the end of each iteration.
However, foreach provides an easy way to iterate over arrays, and it is only used with arrays and objects.
Explain how you can update Memcached when you make changes to PHP?
When PHP changes you can update Memcached by
Clearing the Cache proactively: Clearing the cache when an insert or update is made
Resetting the Cache: It is similar to the first method but rather than just deleting the keys and waiting for the next request for the data to refresh the cache, reset the values after the insert or update.
Which cryptographic extension provide generation and verification of digital signatures?
The PHP-OpenSSL extension provides several cryptographic operations including generation and verification of digital signatures.
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How is a constant defined in a PHP script?
The define() directive lets us defining a constant as follows:
define ("ACONSTANT", 123);
How can you pass a variable by reference?
To be able to pass a variable by reference, we use an ampersand in front of it, as follows $var1 = &$var2
What Is File Upload?
File upload is Web page function which allows visitor to specify a file on the browser's system and submit it to the Web server. This is a very useful function for many interactive Web sites. Some examples are:
Web base email systems for users to send attachments.
Forums that allows user to submit pictures.
Web sites file managers for users to build their own Web pages.
Which HTML Tag Allows Users to Specify a File for Uploading?
To present an input field on your Web page to allow users to specify a local file to upload, you need to use the <INPUT TYPE="FILE" ...> tag inside a <FORM ...> tag. The <INPUT TYPE="FILE" ...> will be displayed as a text input field followed by a button called "Browse...". Users can either enter the full path name of a local file, or click Browse button to go through a dialog box to select a file interactively. The following PHP code shows you a good example of the file upload tag:
<?php
print("<html><form>n");
print("<input type=file>n");
print("<input type=submit>n");
print("</form></html>n");
?>
What Is The Difference Between Char And Varchar Data Types?
CHAR is a fixed length data type. CHAR(n) will take n characters of storage even if you enter less than n characters to that column. For example, "Hello!" will be stored as "Hello! " in CHAR(10) column.
VARCHAR is a variable length data type. VARCHAR(n) will take only the required storage for the actual number of characters entered to that column. For example, "Hello!" will be stored as "Hello!" in VARCHAR(10) column.
How Can We Encrypt And Decrypt A Data Present In A Mysql Table Using Mysql?
AES_ENCRYPT() and AES_DECRYPT().
How Can We Change The Name Of A Column Of A Table?
MySQL query to rename table: RENAME TABLE tbl_name TO new_tbl_name
or,
ALTER TABLE tableName CHANGE OldName newName.
How Can Increase The Performance Of Mysql Select Query?
We can use LIMIT to stop MySql for further search in table after we have received our required no. of records, also we can use LEFT JOIN or RIGHT JOIN instead of full join in cases we have related data in two or more tables.
Will Comparison Of String "10" And Integer 11 Work In Php?
Yes, internally PHP will cast everything to the integer type, so numbers 10 and 11 will be compared.
What Type Of Inheritance That Php Supports?
In PHP an extended class is always dependent on a single base class, that is, multiple inheritance is not supported. Classes are extended using the keyword 'extends'.
What Is The Functionality Of Md5 Function In Php?
string md5(string)
It calculates the MD5 hash of a string. The hash is a 32-character hexadecimal number.
How Can I Load Data From A Text File Into A Table?
The MySQL provides a LOAD DATA INFILE command. You can load data from a file.
Great tool but you need to make sure that:
a) Data must be delimited.
b) Data fields must match table columns correctly.
How Can We Know The Number Of Days Between Two Given Dates Using Mysql?
Use DATEDIFF()
SELECT DATEDIFF(NOW(),'2006-07-01');
How Can We Change The Data Type Of A Column Of A Table?
This will change the data type of a column:
ALTER TABLE table_name CHANGE colm_name same_colm_name [new data type].
How Can We Know That A Session Is Started Or Not?
A session starts by session_start() function.
This session_start() is always declared in header portion. it always declares first. then we write session_ register().
How Many Ways We Can Give The Output To A Browser?
HTML output
PHP, ASP, JSP, Servlet Function
Script Language output Function
Different Type of embedded Package to output to a browser.
Please Give A Regular Expression (preferably Perl/preg Style), Which Can Be Used To Identify The Url From Within A Html Link Tag?
Try this: /href="([^"]*)"/i.
Give The Syntax Of Grant Commands?
The generic syntax for GRANT is as following
GRANT [rights] on [database] TO [username@hostname] IDENTIFIED BY [password]
Now rights can be:
a) ALL privilages
b) Combination of CREATE, DROP, SELECT, INSERT, UPDATE and DELETE etc.
We can grant rights on all databse by usingh *.* or some specific database by database.* or a specific table by database.table_name.
What Are The Different Ways To Login To A Remote Server? Explain The Means, Advantages And Disadvantages?
There is at least 3 ways to logon to a remote server:
Use ssh or telnet if you concern with security
You can also use rlogin to logon to a remote server.
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