Which of the following problem in file system data processing says Making changes to an existing file structure can be difficult in a file system environment.

		Difficulty of getting quick answers
		Lack of security and limited data sharing
		Extensive programming
		All of the above

Unary operator that yields a vertical subset of a table

		Select
		Project
		Intersect
		Difference

Logical design of database is called as ______________

		Database Instance
		Database Schema
		Database Snapshot
		None of these

File structure is changed without affecting the applications ability to access the data is called as_________.

		Structural dependence
		Structural independence
		Data dependence
		Data independence