WorksheetsDBMS Online Quiz-1
Total questions: 15
Worksheet time: 13mins
What is Data Abstraction?
Database systems comprise of complex data-structures.
In order to make the system efficient in terms of retrieval of data, and reduce complexity in terms of usability of users, developers use abstraction
hide irrelevant details from the users.
None of Above
There are mainly how many types of data abstraction are there
1
2
3
4
Identify true options of data abstraction
Internal Level
Conceptual Level
External Level
None of Above
Three Tier Architecture can be called as ANSI SPARC architecture also
True
False
Fact about internal level schema
The internal schema is the lowest level of data abstraction.
The internal view tells us what data is stored in the database and how.
It never deals with the physical devices. Instead, internal schema views a physical device as a collection of physical pages
It helps you to keeps information about the actual representation of the entire database.
Fact about conceptual schema
Defines all database entities, their attributes, and their relationships
Security and integrity information
In the conceptual level, the data available to a user must be contained in or derivable from the physical level
üThis logical level comes between the user level and physical storage view. However, there is only single conceptual view of a single database.
Identify true points for database schema
You can manage data independent of the physical storage
Faster Migration to new graphical environments
It is more secure as the client doesn't have direct access to the database business logic
In case of the failure of the one-tier no data loss as you are always secure by accessing the other tier
Identify points which are not related to database schema
Difficult to set up and maintain
Complete DB Schema is a easy structure which is difficult to understand for every one
The physical separation of the tiers can not affect the performance of the Database
None of the above
The main purpose of data abstraction is achieving data independence in order to save time and cost required when the database is modified or altered.
True
False
There are mainly two types of data independence identify them
Physical
NA
Tactical
Logical
Data Independence is defined as a property of DBMS that helps you to change the Database schema at one level of a database system without requiring to change the schema at the next higher level.
True
False
Logical Data Independence is the ability to change the conceptual scheme without changing
External views
External API or programs
External Name
External DNS
Hashing is an example of Physical Independence
True
False
Add a new attribute is an example of logical independence
False
True
Identify true points about data independence
Helps you to improve the quality of the data
Database incongruity is vastly reduced
You don't need to alter data structure in application programs
It allows you to improve state which is undamaged or undivided
