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WorksheetsWeek 3- lecture (DATA MODELS)
Total questions: 13
Worksheet time: 7mins
What is data model?
Simple representations of complex real-world data structures
Iterative and progressive process of creating a specific data model for a determined problem domain
Abstraction of a real-world object or event
Below are the reasons why the data model is important EXCEPT
Are a communication tool
Give an overall view of the database
Organize data for •various users
Are an abstraction for the creation of bad database
Which are the basic building block(s) for data model?
Hint: Please tick more than one answer
Entity
Relationship
Constraint
Cardinality
Written documentation is one of the source of Business Rules
True
False
The picture above is example of
Network Model
Hierarchical Model
Object Oriented Model
No SQL
(a) uses graphic representations to model database components.
What is the relationship shown by the above Entity Relationship Diagram(ERD)?
one-to-one
many-to-many
one-to-many
What are the 3 characteristics of Big Data?
Volume,Velocity,Variety
Volume,Validate,Vaganza
Velocity, Vast, Vain
There are __________ levels of data abstraction.
3
4
5
6
Which of the following is a Data Model?
Entity-Relationship model
Relational data model
Object-Based data model
All of the above
Complete this sentence: In the three-layer architecture, between the external layer and the conceptual/logical layer, there is …
physical data independence
logical data independence
no independence, they are basically the same thing
the internal layer
Which statement is correct?
Statement A: The middle layer of the three-layer architecture consists of both the conceptual data model and the logical data model. The logical data model is physically implemented in the internal layer.
Statement B: The top level of the three-layer architecture is the external layer. Views for one or more applications always offer a window on the complete logical model.
Only sentence A is right
Only sentence B is right
Sentences A and B are right
Neither A nor B is right
Which statement is correct?
Statement A: Physical data independence implies that neither the applications nor the views or logical data model must be changed when changes are made to the data storage specifications in the internal data model.
Statement B: Logical data independence implies that software applications are minimally affected by changes in the conceptual or logical data model.
Only A
Only B
A and B
Neither A nor B
