Question { Emsang, 138444 }

What are constraints? Explain different types of
constraints?

Answer

constraint is a rule which can not be voilated by end users.
Different types of constraints are available.They are:-
1)default constraint:-which is used to define a default
value.
2)primary key:-the key which does not allows duplication
and null values.
3)foreign key:-the key used to refer primary key defined
field in another table and it allows duplication.
4)null:-which allows NULL values.
5)not null:-which does not allows NULL values.
6)unique key:-which does not allows duplication but allows
NULL values.

Question { Emsang, 138444 }

What are constraints? Explain different types of
constraints?

Answer

Including these it also contains check constraint.
check constraint:-It specifies a range of values witn in
which the attribute should take

Question { 6591 }

What is Remote Procedure Call?

Answer

Remote procedure call is used to mount remote clients to
the servers.

Question { 3i Infotech, 179556 }

What is the difference between join and union.

Answer

we can join two tables by 'join' if they have common
field.we can union two tables irrespective of common field.