--------------------------------------------------------------------------------------------------------------------------------
What's PHP ?
The PHP Hypertext Preprocessor is a programming language that allows web developers to create dynamic content that interacts with databases. PHP is basically used for developing web based software applications.
--------------------------------------------------------------------------------------------------------------------------------
The PHP Hypertext Preprocessor is a programming language that allows web developers to create dynamic content that interacts with databases. PHP is basically used for developing web based software applications.
--------------------------------------------------------------------------------------------------------------------------------
What Is a Session?
A session is a logical object created by the PHP engine to allow you to preserve data across subsequent HTTP requests.
There is only one session object available to your PHP scripts at any time. Data saved to the session by a script can be retrieved by the same script or another script when requested from the same visitor.
Sessions are commonly used to store temporary data to allow multiple PHP pages to offer a complete functional transaction for the same visitor.
--------------------------------------------------------------------------------------------------------------------------------
A session is a logical object created by the PHP engine to allow you to preserve data across subsequent HTTP requests.
There is only one session object available to your PHP scripts at any time. Data saved to the session by a script can be retrieved by the same script or another script when requested from the same visitor.
Sessions are commonly used to store temporary data to allow multiple PHP pages to offer a complete functional transaction for the same visitor.
--------------------------------------------------------------------------------------------------------------------------------
What is meant by PEAR in php?
PEAR is the next revolution in PHP. This repository is bringing higher level programming to PHP. PEAR is a framework and distribution system for reusable PHP components. It eases installation by bringing an automated wizard, and packing the strength and experience of PHP users into a nicely organised OOP library. PEAR also provides a command-line interface that can be used to automatically install "packages"
Answer2:
PEAR is short for "PHP Extension and Application Repository" and is pronounced just like the fruit. The purpose of PEAR is to provide:
A structured library of open-sourced code for PHP users
A system for code distribution and package maintenance
A standard style for code written in PHP
The PHP Foundation Classes (PFC),
The PHP Extension Community Library (PECL),
A web site, mailing lists and download mirrors to support the PHP/PEAR community
PEAR is a community-driven project with the PEAR Group as the governing body. The project has been founded by Stig S. Bakken in 1999 and quite a lot of people have joined the project since then.
PEAR is the next revolution in PHP. This repository is bringing higher level programming to PHP. PEAR is a framework and distribution system for reusable PHP components. It eases installation by bringing an automated wizard, and packing the strength and experience of PHP users into a nicely organised OOP library. PEAR also provides a command-line interface that can be used to automatically install "packages"
Answer2:
PEAR is short for "PHP Extension and Application Repository" and is pronounced just like the fruit. The purpose of PEAR is to provide:
A structured library of open-sourced code for PHP users
A system for code distribution and package maintenance
A standard style for code written in PHP
The PHP Foundation Classes (PFC),
The PHP Extension Community Library (PECL),
A web site, mailing lists and download mirrors to support the PHP/PEAR community
PEAR is a community-driven project with the PEAR Group as the governing body. The project has been founded by Stig S. Bakken in 1999 and quite a lot of people have joined the project since then.
--------------------------------------------------------------------------------------------------------------------------------
How can we know the number of days between two given dates using PHP?
Simple arithmetic:
$date1 = date('Y-m-d');
$date2 = '2006-07-01';
$days = (strtotime() - strtotime()) / (60 * 60 * 24);
echo "Number of days since '2006-07-01': $days";
--------------------------------------------------------------------------------------------------------------------------------
How can we repair a MySQL table?
The syntex for repairing a mysql table is:
REPAIR TABLE tablename
REPAIR TABLE tablename QUICK
REPAIR TABLE tablename EXTENDED
This command will repair the table specified.
If QUICK is given, MySQL will do a repair of only the index tree.
If EXTENDED is given, it will create index row by row.
--------------------------------------------------------------------------------------------------------------------------------
REPAIR TABLE tablename
REPAIR TABLE tablename QUICK
REPAIR TABLE tablename EXTENDED
This command will repair the table specified.
If QUICK is given, MySQL will do a repair of only the index tree.
If EXTENDED is given, it will create index row by row.
--------------------------------------------------------------------------------------------------------------------------------
What is the difference between $message and $$message?
$message is a simple variable whereas $$message is a reference variable. Example:
$user = 'bob'
is equivalent to
$holder = 'user';
$$holder = 'bob';
They are both variables. But $message is a variable with a fixed name. $$message is a variable who's name is stored in $message. For example, if $message contains "var", $$message is the same as $var.
$message is a simple variable whereas $$message is a reference variable. Example:
$user = 'bob'
is equivalent to
$holder = 'user';
$$holder = 'bob';
They are both variables. But $message is a variable with a fixed name. $$message is a variable who's name is stored in $message. For example, if $message contains "var", $$message is the same as $var.
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What Is a Persistent Cookie?
A persistent cookie is a cookie which is stored in a cookie file permanently on the browser's computer. By default, cookies are created as temporary cookies which stored only in the browser's memory. When the browser is closed, temporary cookies will be erased. You should decide when to use temporary cookies and when to use persistent cookies based on their differences:
*Temporary cookies can not be used for tracking long-term information.
*Persistent cookies can be used for tracking long-term information.
*Temporary cookies are safer because no programs other than the browser can access them.
*Persistent cookies are less secure because users can open cookie files see the cookie values.
--------------------------------------------------------------------------------------------------------------------------------
What does a special set of tags <?= and ?> do in PHP?
The output is displayed directly to the browser.
The output is displayed directly to the browser.
--------------------------------------------------------------------------------------------------------------------------------
How do you define a constant?
Via define() directive, like define ("MYCONSTANT", 100);
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Via define() directive, like define ("MYCONSTANT", 100);
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What are the differences between require and include, include_once?
require_once() and include_once() are both the functions to include and evaluate the specified file only once. If the specified file is included previous to the present call occurrence, it will not be done again.
But require() and include() will do it as many times they are asked to do.
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. The major difference between include() and require() is that in failure include() produces a warning message whereas require() produces a fatal errors.
All three are used to an include file into the current page.
If the file is not present, require(), calls a fatal error, while in include() does not.
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. It des not call a fatal error if file not exists. require_once() does the same as include_once(), but it calls a fatal error if file not exists.
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.
require_once() and include_once() are both the functions to include and evaluate the specified file only once. If the specified file is included previous to the present call occurrence, it will not be done again.
But require() and include() will do it as many times they are asked to do.
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. The major difference between include() and require() is that in failure include() produces a warning message whereas require() produces a fatal errors.
All three are used to an include file into the current page.
If the file is not present, require(), calls a fatal error, while in include() does not.
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. It des not call a fatal error if file not exists. require_once() does the same as include_once(), but it calls a fatal error if file not exists.
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 is meant by urlencode and urldecode?
urlencode() returns the URL encoded version of the given string. URL coding converts special characters into % signs followed by two hex digits. For example: urlencode("10.00%") will return "10%2E00%25". URL encoded strings are safe to be used as part of URLs.
urldecode() returns the URL decoded version of the given string.
string urlencode(str) - Returns the URL encoded version of the input string. String values to be used in URL query string need to be URL encoded. In the URL encoded version:
Alphanumeric characters are maintained as is.
Space characters are converted to "+" characters.
Other non-alphanumeric characters are converted "%" followed by two hex digits representing the converted character.
string urldecode(str) - Returns the original string of the input URL encoded string.
For example:
$discount ="10.00%";
$url = "http://domain.com/submit.php?disc=".urlencode($discount);
echo $url;
you will get "http://domain.com/submit.php?disc=10%2E00%25".
--------------------------------------------------------------------------------------------------------------------------------
How To Get the Uploaded File Information in the Receiving Script?
Once the Web server received the uploaded file, it will call the PHP script specified in the form action attribute to process them. This receiving PHP script can get the uploaded file information through the predefined array called $_FILES. Uploaded file information is organized in $_FILES as a two-dimensional array as:
$_FILES[$fieldName]['name'] - The Original file name on the browser system.
$_FILES[$fieldName]['type'] - The file type determined by the browser.
$_FILES[$fieldName]['size'] - The Number of bytes of the file content.
$_FILES[$fieldName]['tmp_name'] - The temporary filename of the file in which the uploaded file was stored on the server.
$_FILES[$fieldName]['error'] - The error code associated with this file upload.
The $fieldName is the name used in the <INPUT TYPE=FILE, NAME=fieldName>.
--------------------------------------------------------------------------------------------------------------------------------
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
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MySQL fetch object will collect first single matching record where mysql_fetch_array will collect all matching records from the table in an array
--------------------------------------------------------------------------------------------------------------------------------
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.
--------------------------------------------------------------------------------------------------------------------------------
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.
--------------------------------------------------------------------------------------------------------------------------------
I am trying to assign a variable the value of 0123, but it keeps coming
up with a different number, what’s the problem?
PHP Interpreter treats numbers beginning with 0 as octal. Look at the similar PHP interview questions for more numeric problems.
PHP Interpreter treats numbers beginning with 0 as octal. Look at the similar PHP interview questions for more numeric problems.
--------------------------------------------------------------------------------------------------------------------------------
What’s PHP ?
The PHP Hypertext Preprocessor is a programming language that allows
web developers to create dynamic content that interacts with databases.
PHP is basically used for developing web based software applications.What Is a Session?
A session is a logical object created by the PHP engine to allow you
to preserve data across subsequent HTTP requests.There is only one
session object available to your PHP scripts at any time. Data saved to
the session by a script can be retrieved by the same script or another
script when requested from the same visitor.Sessions are commonly used
to store temporary data to allow multiple PHP pages to offer a complete
functional transaction for the same visitor.
--------------------------------------------------------------------------------------------------------------------------------
What is meant by PEAR in php?
--------------------------------------------------------------------------------------------------------------------------------
What is meant by PEAR in php?
PEAR is the next revolution in PHP. This repository is bringing
higher level programming to PHP. PEAR is a framework and distribution
system for reusable PHP components. It eases installation by bringing an
automated wizard, and packing the strength and experience of PHP users
into a nicely organised OOP library. PEAR also provides a command-line
interface that can be used to automatically install “packages”
PEAR is short for “PHP Extension and
Application Repository” and is pronounced just like the fruit. The
purpose of PEAR is to provide:
A structured library of open-sourced code for PHP users
A system for code distribution and package maintenance
A standard style for code written in PHP
The PHP Foundation Classes (PFC),
The PHP Extension Community Library (PECL),
A web site, mailing lists and download mirrors to support the PHP/PEAR community
PEAR is a community-driven project with the PEAR Group as the
governing body. The project has been founded by Stig S. Bakken in 1999
and quite a lot of people have joined the project since then.
--------------------------------------------------------------------------------------------------------------------------------
How can we know the number of days between two given dates using PHP?
--------------------------------------------------------------------------------------------------------------------------------
How can we know the number of days between two given dates using PHP?
Simple arithmetic:
$date1 = date(‘Y-m-d’);
$date2 = ’2006-07-01′;
$days = (strtotime() – strtotime()) / (60 * 60 * 24);
echo “Number of days since ’2006-07-01′: $days”;
--------------------------------------------------------------------------------------------------------------------------------
How can we repair a MySQL table?
The syntex for repairing a mysql table is:
--------------------------------------------------------------------------------------------------------------------------------
How can we repair a MySQL table?
The syntex for repairing a mysql table is:
REPAIR TABLE tablename
REPAIR TABLE tablename QUICK
REPAIR TABLE tablename EXTENDED
This command will repair the table specified.
If QUICK is given, MySQL will do a repair of only the index tree.
If EXTENDED is given, it will create index row by row.
--------------------------------------------------------------------------------------------------------------------------------
What is the difference between $message and $$message?
--------------------------------------------------------------------------------------------------------------------------------
What is the difference between $message and $$message?
$message is a simple variable whereas $$message is a reference variable. Example:
$user = ‘bob’
is equivalent to
$holder = ‘user’;
$$holder = ‘bob’;Anwser 2:
They are both variables. But $message is a variable with a fixed
name. $$message is a variable who’s name is stored in $message. For
example, if $message contains “var”, $$message is the same as $var.
--------------------------------------------------------------------------------------------------------------------------------
What Is a Persistent Cookie?
--------------------------------------------------------------------------------------------------------------------------------
What Is a Persistent Cookie?
A persistent cookie is a cookie which is stored in a cookie file permanently on the browser’s computer. By default, cookies are created as temporary cookies which stored only in the browser’s memory. When the browser is closed, temporary cookies will be erased. You should decide when to use temporary cookies and when to use persistent cookies based on their differences:
*Temporary cookies can not be used for tracking long-term information.
*Persistent cookies can be used for tracking long-term information.
*Temporary cookies are safer because no programs other than the browser can access them.
*Persistent cookies are less secure because users can open cookie files see the cookie values.
--------------------------------------------------------------------------------------------------------------------------------
What does a special set of tags <?= and ?> do in PHP?
--------------------------------------------------------------------------------------------------------------------------------
What does a special set of tags <?= and ?> do in PHP?
The output is displayed directly to the browser.How do you define a constant?
Via define() directive, like define (“MYCONSTANT”, 100);
--------------------------------------------------------------------------------------------------------------------------------
What are the differences between require and include, include_once?
--------------------------------------------------------------------------------------------------------------------------------
What are the differences between require and include, include_once?
require_once() and include_once() are both the functions to include and evaluate the specified file only once. If the specified file is included previous to the present call occurrence, it will not be done again.But require() and include() will do it as many times they are asked to do.
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.
The major difference between include() and require() is that in failure
include() produces a warning message whereas require() produces a fatal
errors.
All three are used to an include file into the current page.
If the file is not present, require(), calls a fatal error, while in include() does not.
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.
It des not call a fatal error if file not exists. require_once() does
the same as include_once(), but it calls a fatal error if file not
exists.
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 is meant by urlencode and urldecode?
urlencode() returns the URL encoded version of the given string. URL coding converts special characters into % signs followed by two hex digits. For example: urlencode(“10.00%”) will return “10%2E00%25″. URL encoded strings are safe to be used as part of URLs.
--------------------------------------------------------------------------------------------------------------------------------
What is meant by urlencode and urldecode?
urlencode() returns the URL encoded version of the given string. URL coding converts special characters into % signs followed by two hex digits. For example: urlencode(“10.00%”) will return “10%2E00%25″. URL encoded strings are safe to be used as part of URLs.
urldecode() returns the URL decoded version of the given string.Anwser 2:
string urlencode(str) – Returns the URL encoded version of the input
string. String values to be used in URL query string need to be URL
encoded. In the URL encoded version:
Alphanumeric characters are maintained as is.
Space characters are converted to “+” characters.
Other non-alphanumeric characters are converted “%” followed by two hex digits representing the converted character.
string urldecode(str) – Returns the original string of the input URL encoded string.For example:
$discount =”10.00%”;
$url = “http://domain.com/submit.php?disc=”.urlencode($discount);
echo $url;You will get “http://domain.com/submit.php?disc=10%2E00%25″.
--------------------------------------------------------------------------------------------------------------------------------
How To Get the Uploaded File Information in the Receiving Script?
--------------------------------------------------------------------------------------------------------------------------------
How To Get the Uploaded File Information in the Receiving Script?
Once the Web server received the uploaded file, it will call the PHP script specified in the form action attribute to process them. This receiving PHP script can get the uploaded file information through the predefined array called $_FILES. Uploaded file information is organized in $_FILES as a two-dimensional array as:
$_FILES[$fieldName]['name'] – The Original file name on the browser system.
$_FILES[$fieldName]['type'] – The file type determined by the browser.
$_FILES[$fieldName]['size'] – The Number of bytes of the file content.
$_FILES[$fieldName]['tmp_name'] – The temporary filename of the file in which the uploaded file was stored on the server.
$_FILES[$fieldName]['error'] – The error code associated with this file upload.
The $fieldName is the name used in the <INPUT TYPE=FILE, NAME=fieldName>.
--------------------------------------------------------------------------------------------------------------------------------
What is the difference between mysql_fetch_object and mysql_fetch_array?
--------------------------------------------------------------------------------------------------------------------------------
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
--------------------------------------------------------------------------------------------------------------------------------
How can I execute a PHP script using command line?
--------------------------------------------------------------------------------------------------------------------------------
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.I am
trying to assign a variable the value of 0123, but it keeps coming up
with a different number, what’s the problem?
PHP Interpreter treats numbers beginning with 0 as octal. Look at the
similar PHP interview questions for more numeric problems.Would I use
print “$a dollars” or “{$a} dollars” to print out the amount of dollars
in this example?
In this example it wouldn’t matter, since
the variable is all by itself, but if you were to print something like
“{$a},000,000 mln dollars”, then you definitely need to use the
braces.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))?
Total 5 types of tables we can create
1. MyISAM2. Heap
3. Merge
4. INNO DB
5. ISAM
MyISAM is the default storage engine as of MySQL 3.23. When you fire the above create query MySQL will create a MyISAM table.
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How To Create a Table?
--------------------------------------------------------------------------------------------------------------------------------
How To Create a Table?
If you want to create a table, you can run the CREATE TABLE statement as shown in the following sample script:
<?php
include “mysql_connection.php”;
$sql = “CREATE TABLE Tech_links (“
. ” id INTEGER NOT NULL”
. “, url VARCHAR(80) NOT NULL”
. “, notes VARCHAR(1024)”
. “, counts INTEGER”
. “, time TIMESTAMP DEFAULT sysdate()”
. “)”;
if (mysql_query($sql, $con)) {
print(“Table Tech_links created.\n”);
} else {
print(“Table creation failed.\n”);
}
mysql_close($con);
?>
Remember that mysql_query() returns TRUE/FALSE on CREATE statements. If you run this script, you will get something like this:
Table Tech_links created.
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How can we encrypt the username and password using PHP?
--------------------------------------------------------------------------------------------------------------------------------
How can we encrypt the username and password using PHP?
You can encrypt a password with the following Mysql>SET PASSWORD=PASSWORD(“Password”);
You can use the MySQL PASSWORD() function to encrypt username and password. For example,
INSERT into user (password, …) VALUES (PASSWORD($password”)), …);
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How do you pass a variable by value?
--------------------------------------------------------------------------------------------------------------------------------
How do you pass a variable by value?
Just like in C++, put an ampersand in front of it, like $a = &$b
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What is the functionality of the functions STRSTR() and STRISTR()?
--------------------------------------------------------------------------------------------------------------------------------
What is the functionality of the functions STRSTR() and STRISTR()?
string strstr ( string haystack, string needle ) returns part of
haystack string from the first occurrence of needle to the end of
haystack. This function is case-sensitive.
stristr() is idential to strstr() except that it is case
insensitive.When are you supposed to use endif to end the conditional
statement?
When the original if was followed by : and then the code block without braces.How can we send mail using JavaScript?
No. There is no way to send emails directly using JavaScript.
But you can use JavaScript to execute a client side email program send the email using the “mailto” code. Here is an example:
function myfunction(form)
{
tdata=document.myform.tbox1.value;
location=”mailto:mailid@domain.com?subject=…”;
return true;
}
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What is the functionality of the function strstr and stristr?
--------------------------------------------------------------------------------------------------------------------------------
What is the functionality of the function strstr and stristr?
strstr() returns part of a given string from the first occurrence of a
given substring to the end of the string. For example:
strstr(“user@example.com”,”@”) will return “@example.com”.
stristr() is idential to strstr() except that it is case
insensitive.What is the difference between ereg_replace() and
eregi_replace()?
eregi_replace() function is identical to
ereg_replace() except that it ignores case distinction when matching
alphabetic characters.
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How do I find out the number of parameters passed into function9. ?
--------------------------------------------------------------------------------------------------------------------------------
How do I find out the number of parameters passed into function9. ?
func_num_args() function returns the number of parameters passed
in.What is the purpose of the following files having extensions: frm,
myd, and myi? What these files contain?
In MySQL, the default table type is MyISAM.
Each MyISAM table is stored on disk in three files. The files have
names that begin with the table name and have an extension to indicate
the file type.
The ‘.frm’ file stores the table definition.
The data file has a ‘.MYD’ (MYData) extension.
The index file has a ‘.MYI’ (MYIndex) extension,
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If the variable $a is equal to 5 and variable $b is equal to character a, what’s the value of $$b?
--------------------------------------------------------------------------------------------------------------------------------
If the variable $a is equal to 5 and variable $b is equal to character a, what’s the value of $$b?
100, it’s a reference to existing variable.
--------------------------------------------------------------------------------------------------------------------------------
How To Protect Special Characters in Query String?
--------------------------------------------------------------------------------------------------------------------------------
How To Protect Special Characters in Query String?
If you want to include special characters like spaces in the query
string, you need to protect them by applying the urlencode() translation
function. The script below shows how to use urlencode():
<?php
print(“<html>”);
print(“<p>Please click the links below”
.” to submit comments about TECHPreparation.com:</p>”);
$comment = ‘I want to say: “It\’s a good site! :->”‘;
$comment = urlencode($comment);
print(“<p>”
.”<a href=\”processing_forms.php?name=Guest&comment=$comment\”>”
.”It’s an excellent site!</a></p>”);
$comment = ‘This visitor said: “It\’s an average site! “‘;
$comment = urlencode($comment);
print(“<p>”
.’<a href=”processing_forms.php?’.$comment.’”>’
.”It’s an average site.</a></p>”);
print(“</html>”);
?>
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Are objects passed by value or by reference?
--------------------------------------------------------------------------------------------------------------------------------
Are objects passed by value or by reference?
Everything is passed by value.
--------------------------------------------------------------------------------------------------------------------------------
What are the differences between DROP a table and TRUNCATE a table?
DROP TABLE table_name – This will delete the table and its data.
TRUNCATE TABLE table_name – This will delete the data of the table, but not the table definition.
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How do you call a constructor for a parent class?
--------------------------------------------------------------------------------------------------------------------------------
How do you call a constructor for a parent class?
parent::constructor($value)
--------------------------------------------------------------------------------------------------------------------------------
WHAT ARE THE DIFFERENT TYPES OF ERRORS IN PHP?
Here are three basic types of runtime errors in PHP:
1. Notices: These are trivial, non-critical errors that PHP
encounters while executing a script – for example, accessing a variable
that has not yet been defined. By default, such errors are not displayed
to the user at all – although you can change this default behavior.
2. Warnings: These are more serious errors – for example, attempting
to include() a file which does not exist. By default, these errors are
displayed to the user, but they do not result in script termination.
3. Fatal errors: These are critical errors – for example,
instantiating an object of a non-existent class, or calling a
non-existent function. These errors cause the immediate termination of
the script, and PHP’s default behavior is to display them to the user
when they take place.
Internally, these variations are represented by twelve different error types
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What’s the special meaning of __sleep and __wakeup?
--------------------------------------------------------------------------------------------------------------------------------
What’s the special meaning of __sleep and __wakeup?
__sleep returns the array of all the variables than need to be saved, while __wakeup retrieves them.
--------------------------------------------------------------------------------------------------------------------------------
How can we submit a form without a submit button?
--------------------------------------------------------------------------------------------------------------------------------
How can we submit a form without a submit button?
If you don’t want to use the Submit button to submit a form, you can
use normal hyper links to submit a form. But you need to use some
JavaScript code in the URL of the link. For example:
<a href=”javascript: document.myform.submit();”>Submit
Me</a> Why doesn’t the following code print the newline properly?
<?php $str = ‘Hello, there.\nHow are you?\nThanks for visiting
techpreparation’; print $str; ?>
Because inside the single quotes the \n character is not interpreted as newline, just as a sequence of two characters – \ and n.
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Would you initialize your strings with single quotes or double quotes?
--------------------------------------------------------------------------------------------------------------------------------
Would you initialize your strings with single quotes or double quotes?
Since the data inside the single-quoted string is not parsed for
variable substitution, it’s always a better idea speed-wise to
initialize a string with single quotes, unless you specifically need
variable substitution.How can we extract string ‘abc.com ‘ from a string
http://info@abc.com using regular expression of php?
We can use the preg_match() function with “/.*@(.*)$/” as
the regular expression pattern. For example:
preg_match(“/.*@(.*)$/”,”http://info@abc.com”,$data);
Ex: Assume we are logging in with username and password.
GET: we are submitting a form to login.php, when we do submit or
similar action, values are sent through visible query string (notice
./login.php?username=…&password=… as URL when executi>
--------------------------------------------------------------------------------------------------------------------------------
What is the difference between the functions unlink and unset?
Sorting functions in PHP:
--------------------------------------------------------------------------------------------------------------------------------
How many ways we can we find the current date using MySQL?
SELECT CURDATE();
When we submit a form, which has the GET method it displays pair of
name/value used in the form at the address bar of the browser preceded
by url. Post method doesn’t display these values.
--------------------------------------------------------------------------------------------------------------------------------
What is the difference between the functions unlink and unset?
unlink() is a function for file system handling. It will simply delete the file in context.
unset() is a function for variable management. It will make a variable undefined.
--------------------------------------------------------------------------------------------------------------------------------
How come the code works, but doesn’t for two-dimensional array of mine?
--------------------------------------------------------------------------------------------------------------------------------
How come the code works, but doesn’t for two-dimensional array of mine?
Any time you have an array with more than one dimension, complex
parsing syntax is required. print “Contents: {$arr[1][2]}” would’ve
worked.How can we register the variables into a session?
session_register($session_var);
$_SESSION['var'] = ‘value’;
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What are the different functions in sorting an array?
--------------------------------------------------------------------------------------------------------------------------------
What are the different functions in sorting an array?
Sorting functions in PHP:
asort()
arsort()
ksort()krsort()
uksort()
sort()
natsort()
rsort()
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How can we know the count/number of elements of an array?
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How can we know the count/number of elements of an array?
2 ways:
a) sizeof($array) – This function is an alias of count()
b) count($urarray) – This function returns the number of elements in an array.
Interestingly if you just pass a simple var instead of an array, count() will return 1.
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How many ways we can pass the variable through the navigation between the pages?
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How many ways we can pass the variable through the navigation between the pages?
At least 3 ways:
1. Put the variable into session in the first page, and get it back from session in the next page.
2. Put the variable into cookie in the first page, and get it back from the cookie in the next page.
3. Put the variable into a hidden form field, and get it back from the form in the next page.What is the maximum length of a table name, a database name, or a field name in MySQL?
Database name: 64 characters
Table name: 64 characters
Column name: 64 characters
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How many ways we can we find the current date using MySQL?
SELECT CURDATE();
SELECT CURRENT_DATE();
SELECT CURTIME();
SELECT CURRENT_TIME();
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Give the syntax of GRANT commands?
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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.Give
the syntax of REVOKE commands?
The generic syntax for revoke is as following
REVOKE [rights] on [database] FROM [username@hostname]
Now rights can be:
a) ALL privileges
b) Combination of CREATE, DROP, SELECT, INSERT, UPDATE and DELETE
etc.We can grant rights on all database by using *.* or some specific
database by database.* or a specific table by database.table_name.
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What is the difference between CHAR and VARCHAR data types?
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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.
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