1. Difference between DBMS and File System
In File System, files are used to store data while, collections of databases are utilized for the storage of data in DBMS. Although File System and DBMS are two ways of managing data, DBMS clearly has many advantages over File Systems. Typically when using a File System, most tasks such as storage, retrieval and search are done manually and it is quite tedious whereas a DBMS will provide automated methods to complete these tasks. Because of this reason, using a File System will lead to problems like data integrity, data inconsistency and data security, but these problems could be avoided by using a DBMS. Unlike File System, DBMS are efficient because reading line by line is not required and certain control mechanisms are in place.

2. Advantages of DBMS
The database management system has promising potential advantages, which are explained below:
Controlling Redundancy
Integrity can be enforced
Inconsistency can be avoided
Data can be shared
Standards can be enforced

3. Restricting unauthorized access
Solving Enterprise Requirement than Individual Requirement
Providing Backup and Recovery:
Cost of developing and maintaining system is lower
Data Model can be developed
Concurrency Control

4. Disadvantages of DBMS Complexity Size Performance
Higher impact of a failure
Cost of DBMS
Additional Hardware costs
Cost of Conversion

5. Instance
The term instance is typically used to describe a complete database environment, including the RDBMS software, table structure, stored procedures and other functionality. It is most commonly used when administrators describe multiple instances of the same database.

6. schema
the overall design or description of the database is known as database schema or simply schema

7. Data abstraction
Abstraction is the process of recognizing and focusing on important characteristics of a situation or object and leaving/filtering out the un-wanted characteristics of that situation or object.