61⟩ 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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“Learn PHP programming with Interview Questions and Answers and examples.”
139 PHP Questions And Answers
62⟩ With a heredoc syntax, do I get variable substitution inside the heredoc contents?
Yes.
63⟩ How can we register the variables into a session?
session_register($session_var);
$_SESSION['var'] = 'value';
64⟩ What is the difference between characters 23 and x23?
The first one is octal 23, the second is hex 23.
65⟩ For printing out strings, there are echo, print and printf. Explain the differences.
echo is the most primitive of them, and just outputs the contents following the construct to the screen. print is also a construct (so parentheses are optional when calling it), but it returns TRUE on successful output and FALSE if it was unable to print out the string. However, you can pass multiple parameters to echo, like:
<?php echo 'Welcome ', 'to', ' ', 'globalguideline!'; ?>
and it will output the string "Welcome to globalguideline!" print does not take multiple parameters. It is also generally argued that echo is faster, but usually the speed advantage is negligible, and might not be there for future versions of PHP. printf is a function, not a construct, and allows such advantages as formatted output, but it’s the slowest way to print out data out of echo, print and printf.
66⟩ Can we use include ("abc.php") two times in a php page "makeit.php"?
Yes.
67⟩ How can we submit form without a submit button?
We can use a simple JavaScript code linked to an event trigger of any form field. In the JavaScript code, we can call the document.form.submit() function to submit the form. For example: <input type=button value="Save" onClick="document.form.submit()">
68⟩ How can we create a database using PHP and mysql?
We can create MySQL database with the use of mysql_create_db($databaseName) to create a database.
69⟩ How many ways we can retrieve the date in result set of mysql using php?
As individual objects so single record or as a set or arrays.
70⟩ How come the code works, but does not for two-dimensional array of mine?
Any time you have an array with more than one dimension, complex parsing syntax is required. print "Contents: {$arr[1][2]}" would’ve worked.
71⟩ What is the difference between the functions unlink and unset?
unlink() is a function for file system handling. It will simply delete the file in context.
unset() is a function for variable management. It will make a variable undefined.
72⟩ Would you initialize your strings with single quotes or double quotes?
Since the data inside the single-quoted string is not parsed for variable substitution, it’s always a better idea speed-wise to initialize a string with single quotes, unless you specifically need variable substitution.
73⟩ How can we extract string abc.com from a string http//info@abc.com using regular expression of php?
We can use the preg_match() function with "/.*@(.*)$/" as
the regular expression pattern. For example:
preg_match("/.*@(.*)$/","http://info@abc.com",$data);
echo $data[1];
74⟩ What is the special meaning of __sleep and __wakeup?
__sleep returns the array of all the variables than need to be saved, while __wakeup retrieves them.
75⟩ 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>
76⟩ What Is the difference between htmlentities() and htmlspecialchars()?
htmlspecialchars only takes care of <, >, single quote ‘, double quote " and ampersand. htmlentities translates all occurrences of character sequences that have different meaning in HTML.
77⟩ How can we destroy the session, how can we unset the variable of a session?
session_unregister() - Unregister a global variable from the current session
session_unset() - Free all session variables
78⟩ I am writing an application in PHP that outputs a printable version of driving directions. It contains some long sentences, and I am a neat freak, and would like to make sure that no line exceeds 50 characters. How do I accomplish that with PHP?
On large strings that need to be formatted according to some length specifications, use wordwrap() or chunk_split().
79⟩ What is the output of the ucwords function in this example?
$formatted = ucwords("GLOBALGUIDELINE IS COLLECTION OF INTERVIEW QUESTIONS");
print $formatted;
What will be printed is GLOBALGUIDELINE IS COLLECTION OF INTERVIEW QUESTIONS.
ucwords() makes every first letter of every word capital, but it does not lower-case anything else. To avoid this, and get a properly formatted string, it’s worth using strtolower() first.
80⟩ What is the difference between md5(), crc32() and sha1() crypto on PHP?
The major difference is the length of the hash generated. CRC32 is, evidently, 32 bits, while sha1() returns a 128 bit value, and md5() returns a 160 bit value. This is important when avoiding collisions.
