1. View the data without storing the data into the object.
2. Restrict the view of a table i.e. can hide some of columns in the tables.
3. Join two or more tables and show it as one object to user.
4. Restrict the access of a table so that nobody can insert the rows into the table.
1. dml is not possible if that is more than one table.
2. When table is dropped view becomes inactive.. it depends on the table objects.
3. it is also database object so it will occupy the space.
4. Querying from view takes more time than directly querying from the table.