what is advantage of view in database

This is clearly explained here:
http://en.wikipedia.org/wiki/View_%28database%29[^].

—SA

[Also note the article for Database normalization: http://en.wikipedia.org/wiki/Database_normalization[^]

If a database is well designed, the tables will be normalized (there are exceptions due to performance issues). Views let you have a normalized database, and yet be able to see the data in a much easier to read form. — Clifford Nelson]

P.S.:
Thanks to Clifford for an interesting addition and a useful link on the database normalization and related aspect of the use of the views.