Interview Questions

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 * 2.1;

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;

String class objects are immutable objects and they represents strings( sequence of characters)

StringBuffer class objects are mutable objects representing strings and they are Thread safe

StringBuild class objects are also mutable objects representing strings and they are not Thread safe

- The traffic can be measured using the size of the files that are transferred from one place to another (server-client). 

- It can also be measured by the size of the file that is being requested by the client from the server. 

- The number of visitors arriving on the website also involve in the measurement of the traffic using the web hosting platform. 

- The advertisements of the sites take more bandwidth to allow more number of users to be on the website. 

- More number of users provides higher traffic on the website thus it requires more bandwidth on the web hosting sites.

Package is a collection of related classes and interfaces. package declaration should be first statement in a java class.

ClassName refName = new ClassName();

or

ClassName refName;

refName = new ClassName();

Overriding is a method with the same name and arguments as in a parent, whereas overloading is the same method name but different arguments

A record data type represents a data type for that row in a database table. It lets u define your own records and not your own fields.