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Understand the difference between Schema and Instance: A Schema is the overall structure/design of the database (changes rarely), whereas an Instance is the actual data stored at a particular moment (changes frequently).
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Know the Three-Schema Architecture: It consists of External Level (User View), Conceptual Level (Logical Structure), and Internal Level (Physical Storage). This architecture provides data independence.
Remember the two types of Data Independence: Logical Data Independence (changes in conceptual schema do not affect external schema) and Physical Data Independence (changes in internal schema do not affect conceptual schema).
Learn the Database System Environment: It includes Hardware, Software (DBMS), Database, Users, Application Programs, Procedures, and Data Access Languages (SQL) working together to manage data efficiently.
Exam Focus: Be able to draw and explain the Three-Schema Architecture and distinguish between Schema vs Instance with suitable examples.
Present the various users of the DBMS environment and their interactions with the components of the DBMS modules with a neat diagram.
a. How do different schema languages support the architecture? What kind of architecture is followed to support the present DBMS requirements? Explain each level with an example. b. Compare: Physical data independence and logical data independence.
Consider the web based digital library system, i) Suggest the suitable data model that can be used to describe the system with a neat sketch. ii) Identify and explain the ways to achieve data independence in the given system.
Assume that you are developing a web application which has to hold a huge volume of data and should be accessed in a secured and fast manner to perform several operations concurrently without any conflicts. Determine the suitable architecture that is applicable for the given scenario and discuss in detail.
Discuss various component modules of a DBMS and their interactions with a neat diagram.