Nate PHP Most Frequently Asked Latest Interview Questions Answers
What's the difference between __sleep and __wakeup?
__sleep returns the array of all the variables that need to be saved, while __wakeup retrieves them.
What is faster?
1- Combining two variables as follows:
$variable1 = 'Hello ';
$variable2 = 'World';
$variable3 = $variable1.$variable2;
Or
2- $variable3 = "$variable1$variable2";
$variable3 will contain "Hello World". The first code is faster than the second code especially for large large sets of data.
What does $_COOKIE mean?
$_COOKIE is an associative array of variables sent to the current PHP script using the HTTP Cookies.
What does the scope of variables mean?
The scope of a variable is the context within which it is defined. For the most part, all PHP variables only have a single scope. This single scope spans included and required files as well.
Is it possible to submit a form with a dedicated button?
It is possible to use the document.form.submit() function to submit the form. For example: <input type=button value="SUBMIT" onClick="document.form.submit()">
What is the difference between ereg_replace() and eregi_replace()?
The function eregi_replace() is identical to the function ereg_replace() except that it ignores case distinction when matching alphabetic characters.
Is it possible to protect special characters in a query string?
Yes, we use the urlencode() function to be able to protect special characters.
What are the three classes of errors that can occur in PHP?
The three basic classes of errors are notices (non-critical), warnings (serious errors) and fatal errors (critical errors).
What is the difference between characters \034 and \x34?
\034 is octal 34 and \x34 is hex 34.
How can we pass the variable through the navigation between the pages?
It is possible to pass the variables between the PHP pages using sessions, cookies or hidden form fields.
Is it possible to extend the execution time of a PHP script?
The use of the set_time_limit(int seconds) enables us to extend the execution time of a PHP script. The default limit is 30 seconds.
Is it possible to destroy a cookie?
Yes, it is possible by setting the cookie with a past expiration time.
What is the default session time in PHP?
The default session time in php is until the closing of the browser
Is it possible to use COM component in PHP?
Yes, it's possible to integrate (Distributed) Component Object Model components ((D)COM) in PHP scripts which is provided as a framework.
Explain whether it is possible to share a single instance of a Memcache between multiple PHP projects?
Yes, it is possible to share a single instance of Memcache between multiple projects. Memcache is a memory store space, and you can run memcache on one or more servers. You can also configure your client to speak to a particular set of instances. So, you can run two different Memcache processes on the same host and yet they are completely independent. Unless, if you have partitioned your data, then it becomes necessary to know from which instance to get the data from or to put into.
$a and $b: TRUE if both $a and $b are TRUE.
$a & $b: Bits that are set in both $a and $b are set.
What are the two main string operators?
The first is the concatenation operator ('.'), which returns the concatenation of its right and left arguments. The second is ('.='), which appends the argument on the right to the argument on the left.
What does the array operator '===' means?
$a === $b TRUE if $a and $b have the same key/value pairs in the same order and of the same types.
What is the differences between $a != $b and $a !== $b?
!= means inequality (TRUE if $a is not equal to $b) and !== means non-identity (TRUE if $a is not identical to $b).
what is the definition of a session?
A session is a logical object enabling us to preserve temporary data across multiple PHP pages.
How to initiate a session in PHP?
The use of the function session_start() lets us activating a session.
How can you propagate a session id?
You can propagate a session id via cookies or URL parameters.
What is the meaning of a Persistent Cookie?
A persistent cookie is permanently stored in a cookie file on the browser's computer. By default, cookies are temporary and are erased if we close the browser.
When do sessions end?
Sessions automatically end when the PHP script finishes executing but can be manually ended using the session_write_close().
What is the difference between session_unregister() and session_unset()?
The session_unregister() function unregister a global variable from the current session and the session_unset() function frees all session variables.
How Does Firefox Manage Cookies?
FireFox browser allows you to delete old cookies, and gives you options to keep persistent cookies in cookie files until they reach their expiration time. The following tutorial shows you how to manage cookies in FireFox:
• Run FireFox
• Go to Tools/Options
• Click Privacy and then Cookies
• Click the Clear button to delete all old cookies
• Change the Keep Cookies option to "until they expire" to allow persistent cookies to be store a cookie file.
What Are The Options To Transfer Session Ids?
Once a new session is created, its session ID must be transferred to the client browser and included in the next client request, so that the PHP engine can find the same session created by the same visitor. The PHP engine has two options to transfer the session ID to the client browser:
As URL parameter - The Session ID will be embedded in all URLs in the HTML document delivered to the client browser. When the visitor clicks any of those URLs, the session ID will be returned back to the Web server as part of the requesting URL.
As a cookie - The session ID will be delivered as a cookie to the client browser. When visitor requests any other pages on the Web server, the session ID will be returned back to the Web server also as a cookie.
The PHP engine is configured to use URL parameters for transferring session IDs by default.
Is It More Secure To Use Cookies To Transfer Session Ids?
yes, because attacking your Web site using URL parameters is much easier than using cookies.
So if you are the system administrator of your Web server, you should set session.use_only_cookies=1.
If your Web server is provided by a hosting service provider, ask them to set session.use_only_cookies=1.
How can PHP and Javascript interact?
PHP and Javascript cannot directly interact since PHP is a server side language and Javascript is a client-side language. However, we can exchange variables since PHP can generate Javascript code to be executed by the browser and it is possible to pass specific variables back to PHP via the URL.
What is needed to be able to use image function?
GD library is needed to execute image functions.
What is the use of the function 'imagetypes()'?
imagetypes() gives the image format and types supported by the current version of GD-PHP.
Which function gives us the number of affected entries by a query?
mysqli_affected_rows() return the number of entries affected by an SQL query.
What is the difference between mysqli_fetch_object() and mysqli_fetch_array()?
The mysqli_fetch_object() function collects the first single matching record where mysqli_fetch_array() collects all matching records from the table in an array.
How can we access the data sent through the URL with the GET method?
To access the data sent via the GET method, we use $_GET array like this:
www.url.com?var=value
$variable = $_GET["var"]; this will now contain 'value'
How can we access the data sent through the URL with the POST method?
To access the data sent this way, you use the $_POST array.
Imagine you have a form field called 'var' on the form when the user clicks submit to the post form, you can then access the value like this:
$_POST["var"];
What's the difference between __sleep and __wakeup?
__sleep returns the array of all the variables that need to be saved, while __wakeup retrieves them.
What is faster?
1- Combining two variables as follows:
$variable1 = 'Hello ';
$variable2 = 'World';
$variable3 = $variable1.$variable2;
Or
2- $variable3 = "$variable1$variable2";
$variable3 will contain "Hello World". The first code is faster than the second code especially for large large sets of data.
What does $_COOKIE mean?
$_COOKIE is an associative array of variables sent to the current PHP script using the HTTP Cookies.
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| Nate PHP Most Frequently Asked Latest Interview Questions Answers |
What does the scope of variables mean?
The scope of a variable is the context within which it is defined. For the most part, all PHP variables only have a single scope. This single scope spans included and required files as well.
Is it possible to submit a form with a dedicated button?
It is possible to use the document.form.submit() function to submit the form. For example: <input type=button value="SUBMIT" onClick="document.form.submit()">
What is the difference between ereg_replace() and eregi_replace()?
The function eregi_replace() is identical to the function ereg_replace() except that it ignores case distinction when matching alphabetic characters.
Is it possible to protect special characters in a query string?
Yes, we use the urlencode() function to be able to protect special characters.
What are the three classes of errors that can occur in PHP?
The three basic classes of errors are notices (non-critical), warnings (serious errors) and fatal errors (critical errors).
What is the difference between characters \034 and \x34?
\034 is octal 34 and \x34 is hex 34.
How can we pass the variable through the navigation between the pages?
It is possible to pass the variables between the PHP pages using sessions, cookies or hidden form fields.
Is it possible to extend the execution time of a PHP script?
The use of the set_time_limit(int seconds) enables us to extend the execution time of a PHP script. The default limit is 30 seconds.
Is it possible to destroy a cookie?
Yes, it is possible by setting the cookie with a past expiration time.
What is the default session time in PHP?
The default session time in php is until the closing of the browser
Is it possible to use COM component in PHP?
Yes, it's possible to integrate (Distributed) Component Object Model components ((D)COM) in PHP scripts which is provided as a framework.
Explain whether it is possible to share a single instance of a Memcache between multiple PHP projects?
Yes, it is possible to share a single instance of Memcache between multiple projects. Memcache is a memory store space, and you can run memcache on one or more servers. You can also configure your client to speak to a particular set of instances. So, you can run two different Memcache processes on the same host and yet they are completely independent. Unless, if you have partitioned your data, then it becomes necessary to know from which instance to get the data from or to put into.
what the difference between the 'BITWISE AND' operator and the 'LOGICAL AND' operator?
$a and $b: TRUE if both $a and $b are TRUE.
$a & $b: Bits that are set in both $a and $b are set.
What are the two main string operators?
The first is the concatenation operator ('.'), which returns the concatenation of its right and left arguments. The second is ('.='), which appends the argument on the right to the argument on the left.
What does the array operator '===' means?
$a === $b TRUE if $a and $b have the same key/value pairs in the same order and of the same types.
What is the differences between $a != $b and $a !== $b?
!= means inequality (TRUE if $a is not equal to $b) and !== means non-identity (TRUE if $a is not identical to $b).
what is the definition of a session?
A session is a logical object enabling us to preserve temporary data across multiple PHP pages.
How to initiate a session in PHP?
The use of the function session_start() lets us activating a session.
How can you propagate a session id?
You can propagate a session id via cookies or URL parameters.
What is the meaning of a Persistent Cookie?
A persistent cookie is permanently stored in a cookie file on the browser's computer. By default, cookies are temporary and are erased if we close the browser.
When do sessions end?
Sessions automatically end when the PHP script finishes executing but can be manually ended using the session_write_close().
What is the difference between session_unregister() and session_unset()?
The session_unregister() function unregister a global variable from the current session and the session_unset() function frees all session variables.
How Does Firefox Manage Cookies?
FireFox browser allows you to delete old cookies, and gives you options to keep persistent cookies in cookie files until they reach their expiration time. The following tutorial shows you how to manage cookies in FireFox:
• Run FireFox
• Go to Tools/Options
• Click Privacy and then Cookies
• Click the Clear button to delete all old cookies
• Change the Keep Cookies option to "until they expire" to allow persistent cookies to be store a cookie file.
What Are The Options To Transfer Session Ids?
Once a new session is created, its session ID must be transferred to the client browser and included in the next client request, so that the PHP engine can find the same session created by the same visitor. The PHP engine has two options to transfer the session ID to the client browser:
As URL parameter - The Session ID will be embedded in all URLs in the HTML document delivered to the client browser. When the visitor clicks any of those URLs, the session ID will be returned back to the Web server as part of the requesting URL.
As a cookie - The session ID will be delivered as a cookie to the client browser. When visitor requests any other pages on the Web server, the session ID will be returned back to the Web server also as a cookie.
The PHP engine is configured to use URL parameters for transferring session IDs by default.
Is It More Secure To Use Cookies To Transfer Session Ids?
yes, because attacking your Web site using URL parameters is much easier than using cookies.
So if you are the system administrator of your Web server, you should set session.use_only_cookies=1.
If your Web server is provided by a hosting service provider, ask them to set session.use_only_cookies=1.
How can PHP and Javascript interact?
PHP and Javascript cannot directly interact since PHP is a server side language and Javascript is a client-side language. However, we can exchange variables since PHP can generate Javascript code to be executed by the browser and it is possible to pass specific variables back to PHP via the URL.
What is needed to be able to use image function?
GD library is needed to execute image functions.
What is the use of the function 'imagetypes()'?
imagetypes() gives the image format and types supported by the current version of GD-PHP.
Which function gives us the number of affected entries by a query?
mysqli_affected_rows() return the number of entries affected by an SQL query.
What is the difference between mysqli_fetch_object() and mysqli_fetch_array()?
The mysqli_fetch_object() function collects the first single matching record where mysqli_fetch_array() collects all matching records from the table in an array.
How can we access the data sent through the URL with the GET method?
To access the data sent via the GET method, we use $_GET array like this:
www.url.com?var=value
$variable = $_GET["var"]; this will now contain 'value'
How can we access the data sent through the URL with the POST method?
To access the data sent this way, you use the $_POST array.
Imagine you have a form field called 'var' on the form when the user clicks submit to the post form, you can then access the value like this:
$_POST["var"];
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