Q: What is the difference between the functions unlink and unset in PHP?

The function unlink() is to remove a file, where as unset() is used for destroying a variable that was declared earlier

Q: What is the difference between _construct() and _destruct() methods in php?

These two methods are bulid-in methods in php with construct() we can overwride the parent class method The inverse of the __construct() PHP capacity while making another class, is the __destruct() technique The __destruct() technique will consequently keep running, after you've completed with the PHP class

Q: What's the difference between GET() and POST() method?

We can send 1024 bytes utilizing GET() yet POST() can exchange extensive measure of information and POST is the protected strategy than GET technique

Q: What is the purpose $_PHP_SELF variable?

The PHP default variable $_PHP_SELF is utilized for the PHP script name and when you click "submit" catch then same PHP script will be called

Q: What's the difference between Session and Cookie?

The principle distinction amongst sessions and cookies is that sessions are put away on the server, and cookies are put away on the client's PCs in the content record position Cookies can not hold various variables,But Session can hold numerous variablesWe can set expiry for a cookie,The session just stays dynamic the length of the program is openUsers don't have admittance to the information you put away in Session,Since it is put away in the server Session is mostly utilized for login/logout reason while cookies utilizing for client movement following

Q: How to create a basic text file in php?

$filename = "/home/user/guest/newfiletxt"; $file = fopen( $filename, "w" ); if( $file == false ) { echo ( "Error in opening new file" ); exit(); } fwrite( $file, "This is a simple test\n" ); fclose( $file );

Question 1

Will comparison of string "10" and integer 11 work in PHP?

Accepted Answer

Yes, internally PHP will cast everything to the integer type, so numbers 10 and 11 will be compared

Question 2

How can I retrieve values from one database server and store them in other database server using PHP?

Accepted Answer

we can always fetch from one database and rewrite to another Here is a nice solution of it$db1 = mysql_connect("host","user","pwd") mysql_select_db("db1", $db1); $res1 = mysql_query("query",$db1);$db2 = mysql_connect("host","user","pwd") mysql_select_db("db2", $db2); $res2 = mysql_query("query",$db2);At this point you can only fetch records from you previous ResultSet, ie $res1 â€“ But you cannot execute new query in $db1, even if you supply the link as because the link was overwritten by the new dbso at this point the following script will fail $res3 = mysql_query("query",$db1); //this will failSo how to solve that? take a look below $db1 = mysql_connect("host","user","pwd") mysql_select_db("db1", $db1); $res1 = mysql_query("query",$db1); $db2 = mysql_connect("host","user","pwd", true) mysql_select_db("db2", $db2); $res2 = mysql_query("query",$db2); So mysql_connect has another optional boolean parameter which indicates whether a link will be created or not, as we connect to the $db2 with this optional parameter set to 'true', so both link will remain live Now the following query will execute successfully $res3 = mysql_query("query",$db1);

Question 3

How to use HTTP Headers inside PHP? Write the statement through which it can be added?

Accepted Answer

HTTP headers can be used in PHP by redirection which is written as: The headers can be added to HTTP response in PHP using the header() The response headers are sent before any actual response being sent The HTTP headers have to be sent before taking the output of any data The statement above gets included at the top of the script

Question 4

Describe how to create a simple AD rotator script without using database in PHP.

Accepted Answer

Following are the steps to create a simple AD rotator script without using database in PHP: - All the ad’s can be collected in one place and be displayed randomlyrand() function can be used for this purpose - In order to NOT use any database, a flat file can be used to store the ad’s - In order to store the Ad’s information (HTML code), a flat file say “adtxt” can be created - The random number can be stored in a variable $result_random=rand(1, 100); - Conditions can be checked to display the ad’s if($result_random<=70) { echo "Display ad1"; }

Question 5

What is the difference between the functions unlink and unset in PHP?

Accepted Answer

The function unlink() is to remove a file, where as unset() is used for destroying a variable that was declared earlier

Question 6

What is the difference between _construct() and _destruct() methods in php?

Accepted Answer

These two methods are bulid-in methods in php with construct() we can overwride the parent class method The inverse of the __construct() PHP capacity while making another class, is the __destruct() technique The __destruct() technique will consequently keep running, after you've completed with the PHP class

Question 7

What's the difference between GET() and POST() method?

Accepted Answer

We can send 1024 bytes utilizing GET() yet POST() can exchange extensive measure of information and POST is the protected strategy than GET technique

Question 8

What is the purpose $_PHP_SELF variable?

Accepted Answer

The PHP default variable $_PHP_SELF is utilized for the PHP script name and when you click "submit" catch then same PHP script will be called

Question 9

What's the difference between Session and Cookie?

Accepted Answer

The principle distinction amongst sessions and cookies is that sessions are put away on the server, and cookies are put away on the client's PCs in the content record position Cookies can not hold various variables,But Session can hold numerous variablesWe can set expiry for a cookie,The session just stays dynamic the length of the program is openUsers don't have admittance to the information you put away in Session,Since it is put away in the server Session is mostly utilized for login/logout reason while cookies utilizing for client movement following

Question 10

How to create a basic text file in php?

Accepted Answer

$filename = "/home/user/guest/newfiletxt"; $file = fopen( $filename, "w" ); if( $file == false ) { echo ( "Error in opening new file" ); exit(); } fwrite( $file, "This is a simple test
" ); fclose( $file );

Question 11

What is ANALYZE command used for?

Accepted Answer

ANALYZE command is used to perform various functions on index, table, or cluster, as listed below: - It helps in dentifying migrated and chained rows of the table or cluster - It helps in validating the structure of the object - It helps in collecting the statistics about object used by the optimizer They are then stored in the data dictionary - It helps in deleting statistics used by object from the data dictionary

Question 12

What are the uses of synonyms?

Accepted Answer

- Mask the real name and owner of an object - Provide public access to an object - Provide location transparency for tables, views or program units of a remote database - Simplify the SQL statements for database users

Question 13

What are Cursors? Explain Types of cursors in PL/SQL

Accepted Answer

Cursors help you manipulate the information retrieved by select statements This can be done by assigning a name to the cursor Example: CURSOR emp_cur IS SELECT emp_number from employee_tbl where employee_name = name_in; Types of Cursors: Implicit cursors- These cursors are not declared by the programmer They are issued when the SQL statement is executed The open, close and fetching is done by itself Example: UPDATE employee SET salary = salary * 21; Here, an implicit cursor is issued to identify the set of rows in the table which would be affected by the update Explicit cursors- These cursors are defined by programmer They are used in queries that return multiple rows Example: CURSOR emp_cur IS SELECT emp_number from employee_tbl where employee_name = name_in;

Question 14

What are PL/SQL Subprograms? What are its Advantages ?

Accepted Answer

Named PL/SQL blocks of code which can be invoked using parameters are called PL/SQL sub programs Advantages of PL/SQL subprograms are - The application makes a single call to the database to run a block of statements which improves performance against running SQL multiple times This will reduce the number of calls between the database and the application - PL/SQL is secure since the code resides inside the database thus hiding internal database details from the application The application will only make a call to the PL/SQL sub program - PL/SQL and SQL go hand in hand so there would be no need of any translation required between PL/SQL and SQL

Question 15

What is a Trigger? Explain Types of PL/SQL Triggers.

Accepted Answer

A database trigger is procedural code that is automatically executed in response to certain events on a particular table or view in a database The trigger is mostly used for maintaining the integrity of the information on the database Syntax: CREATE OR REPLACE TRIGGER [Trigger Name] [Before / After / Instead Of] ON [schema][table] Types of PL/SQL triggers : > Row trigger - The trigger fires for each ROW affected > Statement trigger - The trigger is fired once when the condition is matched > Before and After trigger - The BEFORE trigger run the trigger action before the insert, update or delete statement The AFTER trigger runs the trigger action after the insert, update or delete statement is executes

Question 16

What are transaction isolation levels supported by Oracle?

Accepted Answer

Oracle supports 3 transaction isolation levels: - Read committed (default) - Serializable transactions - Read only

Question 17

Can you explain how to insert an image in table in oracle?

Accepted Answer

Insert image into a table Create the following table: create table pics_table ( bfile_id number, bfile_desc varchar2(30), bfile_loc bfile, bfile_type varchar2(4)) TABLESPACE appl_data storage (initial 1m next 1m pctincrease 0) Insert Query: INSERT INTO pics_table VALUES(4,'test image',bfilename('GIF_FILES','TestJPG'),'JPEG');

Question 18

Which of the following are elements of SQL?

Accepted Answer

All the above

Question 19

What is DocumentDB ?

Accepted Answer

DocumentDB is a NoSQL document-oriented database and records saves in key-value pairs It's same as the other NoSQL document-oriented such as MongoDB

Question 20

What is the maximum number of Triggers can be applied in a table ?

Accepted Answer

We can apply at max of 12 triggers in a table.

Technology Questions