Instead of giving a bookish Definition, I explained him how my honorable teachers explained to me Here it is "We have lots table being created in Database. Some times we need to consider memory constraints of creating lots of table in the DB. So for example I have table called teachers table having column Name Salary Dept Contact no " but I need to show to students only the Name Dept Contact no than instead of creating a new table I can create a view a virtual table with above column thereby achieving what I want and without taking any memory space "