Previously we discuss about name of the components which present in DBMS.Here we study all those terms in detail and know how it work and what are there functions.There are so many terms we discuss all these one by one and try to understand with the help of real world examples just relate it with real activity.Here we start to discuss all of theseAbstraction :- In DBMS abstraction is also called data abstraction.Data abstraction is a process of hiding non-useful details from user is called data abstraction.With the help of Database we can store large amount of data so by using abstraction developer hide the all irrelevant information from the user and show only essential part.The process in which irrelevant data hide from the user is called data abstraction.Example :-Suppose there is a printer which print 100 copies in 1 min.The user just press the one button and process will start and user receive its output in 1 min.The user does not worry about the backend architecture of printer and does not think how it work and what are its part which make it performing these type of work.All these things just hide  from the user.The user only know about the button and its output.Simply in Databases all the functioning hide from the user with the help of the abstaction and show only the desired part.There are three level of Abstraction:-1).View level:- This level help to explain the user interaction with the databases.View level is highest level of data abstraction.2).Logical level:- With the help of logical level we know about that what data is stored in a database.This level of abstaction present in the middle of the three level abstraction.3).Physical level:- This level of abstraction describe how data store in the database. At this level user get the complex data structure detail. Physial level is the lowest level of abstraction.Here is the example for understanding the level of abstarction clearly.Example: Let’s say we are storing students information in a student table. At physical level these records can be described as blocks of storage (bytes, gigabytes, terabytes etc.) in memory. These details are all hidden from the programmers.At the logical level these information(record) can be explain  as fields and attributes along with their data types, their relationship with each other can be logically implemented. The programmers mostly work at this level because they are well know  such things about database systems.At view level, user just interact with system with the help of GUI and enter the information at the screen, they are not aware of how the data is stored and what data is stored; such details are hidden from them.With the help of this we know how data Abstraction will work and what is its functioning and how it benificial for database system.Instance and Schema:- There are wo terms Instance and Schema both are totally different from each other.But both are very imporatnt for database system.1) Schema:- The term “schema” is defined as  the organization of data as a blueprint of how the database is constructed (divided into database tables in the case of relational databases). The formal definition of a database schema is a set of formulas called integrity constraints applied on a database.Simply, Schema is a Design of the database.The schema of the database is also divideinto three part which are:-? View schema? Logical schema ? Physical schemaAt physical level,  the design of the database is called physical schema. At this level it show how data is stored in a block of storage in the database.At logical level,the design of the database is called logical schema.In this level programmer and DBA(Database Administrator) work in database system.Data is describe as certain type of data records gets stored in a data structures at this level.The last is View Schema,At View level the design of the database is called view schema.It is upper level in this  it descibe the interaction between end user and database.These are all about Schema.Its architecture is quite similar to Abstraction.Schema is part which handle the design property of the database system.Instance Instance is more likely related with Time.In this,at which time data stored in the database that particular moment of time is called instance.The values which are stored in the variable which present in databases at a particular moment time of the time is called the instance of the database.Here we discuss term Abstraction , Instance and Schema.These term are related to the view of the DBMS(DataBase Management System).After that in the next artical we dicuss about the  other following terms which are listed bellow:-  key IndexPrimary keySuper KeyForeign KeyCandidate KeyComposite KeyAlternate keyNormalizationData ModelsE-R modelsRelational modelHierarchical modelDBMS languagesFunctional DependencyConcurrency ControlConstraintsDeadlockFor study more about the detail description related to these term click on the next button.