Question { 7953 }

what is constructer?what are the type of constructer with
example.

Answer

class Shiva
{
public Shiva() // it is a constructor
{
//code
}
}
class Mainclass
{
public static void main(String args[])
{
Shiva obj=new Shiva();
}
}

explanation: the code written in constructor is
automatically executed when we create object for the
class.no need to call the constructor/method again.

point to note:
constructor must not have any return type

Question { 40078 }

what is data independence exactly? give an example

Answer

There are two types of data independence

1. Logical data independence: The ability to change the
logical (conceptual) schema without changing the External
schema (User View) is called logical data independence. For
example, the addition or removal of new entities,
attributes, or relationships to the conceptual schema should
be possible without having to change existing external
schemas or having to rewrite existing application programs.

2 Physical data independence: The ability to change the
physical schema without changing the logical schema is
called physical data independence. For example, a change to
the internal schema, such as using different file
organization or storage structures, storage devices, or
indexing strategy, should be possible without having to
change the conceptual or external schemas.