Latest Technical Interview Answers - 3

Latest Technical Interview Answers - 3
What is the difference between CHAR and VARCHAR data types?
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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 [...]
Give the syntax of REVOKE commands?
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The generic syntax for revoke is as following REVOKE [rights] on [database] FROM [username@hostname] 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 GRANT commands?
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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.
How many ways we can we find the current date using MySQL?
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SELECT CURDATE(); SELECT CURRENT_DATE(); SELECT CURTIME(); SELECT CURRENT_TIME();
How can we find the number of rows in a result set using PHP?
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Here is how can you find the number of rows in a result set in PHP: $result = mysql_query($any_valid_sql, $database_link); $num_rows = mysql_num_rows($result); echo “$num_rows rows found”;
What is the maximum length of a table name, a database name, or a field name in MySQL?
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Database name: 64 characters Table name: 64 characters Column name: 64 characters
How many ways we can pass the variable through the navigation between the pages?
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At least 3 ways: 1. Put the variable into session in the first page, and get it back from session in the next page. 2. Put the variable into cookie in the first page, and get it back from the cookie in the next page. 3. Put the variable into a hidden form field, and get it back [...]
How can we know the count/number of elements of an array?
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2 ways: a) sizeof($array) - This function is an alias of count() b) count($urarray) - This function returns the number of elements in an array. Interestingly if you just pass a simple var instead of an array, count() will return 1.
What are the different functions in sorting an array?
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Sorting functions in PHP: asort() arsort() ksort() krsort() uksort() sort() natsort() rsort()
How can we destroy the session, how can we unset the variable of a session?
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session_unregister() - Unregister a global variable from the current session session_unset() - Free all session variables
What’s the output of the ucwords function in this example?
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$formatted = ucwords(”FYICENTER IS COLLECTION OF INTERVIEW QUESTIONS”); print $formatted; What will be printed is FYICENTER IS COLLECTION OF INTERVIEW QUESTIONS. ucwords() makes every first letter of every word capital, but it does not lower-case anything else. To avoid this, and get a properly formatted string, it’s worth using strtolower() first.
For printing out strings, there are echo, print and printf. Explain the differences.
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echo is the most primitive of them, and just outputs the contents following the construct to the screen. print is also a construct (so parentheses are optional when calling it), but it returns TRUE on successful output and FALSE if it was unable to print out the string. However, you can pass multiple parameters to [...]
How can we submit form without a submit button?
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We can use a simple JavaScript code linked to an event trigger of any form field. In the JavaScript code, we can call the document.form.submit() function to submit the form. For example:
How come the code works, but doesn’t for two-dimensional array of mine?
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Any time you have an array with more than one dimension, complex parsing syntax is required. print “Contents: {$arr[1][2]}” would’ve worked.
What is the difference between the functions unlink and unset?
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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 can we extract string ‘abc.com ‘ from a string http://info@abc.com using regular expression of php?
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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];
Would you initialize your strings with single quotes or double quotes?
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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 submit a form without a submit button?
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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: Submit Me
WHAT ARE THE DIFFERENT TYPES OF ERRORS IN PHP?
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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. [...]
What are the differences between GET and POST methods in form submitting, give the case where we can use GET and we can use POST methods?
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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.