Question 1
(a) (i) What is data model?
(ii) State three types of data model.
(b)(i) List three approaches to data modeling.
(ii) Explain any one approach in 1 (b)(i)
Observation
The expected answers were:
(a)(i) Data model is the organization of data elements and standard on how the data elements relate to one another.
OR
Data model is the representation of the data structures that are required by the database.
OR
Data model is the representation of a real-world situation about which data is to be collected
OR
Data model is the structure and organization of data in database
OR
Data model is the diagram showing inter-relationships between data elements and how they are stored
(ii) Types of data model
- flat model
- hierarchical model
- network model
- relational model
- object-oriented model
- entity relationship model
- document model
- entity-attribute-value model
- star schema
- object relational model
- inverted file model
- multi dimensional model
- semi structured model
- context model
- associative model
- NoSQL model
(b)(i) Approaches to data modelling
- conceptual data model
- enterprise data model
- logical data model
- physical data model
(ii) Conceptual data model
- identifies objects, concepts, entities and relationships between them
- represents the first/initial stage/base in the development of the design of data and data storage.
- is the most abstract form/ highest level/ summary level of data modeling.
Enterprise data model
- creates a graphical model/view of all data used in an organization/ company/ enterprise.
Logical data model
- describes the data in detail as much as possible without regard to how they will be physically implemented in the database.
Physical data model
- is a representation of data/ tables (Table Names, Primary key, Foreign keys, Column/Field Name & Data types) in a DBMS.
The question tested candidates’ knowledge of data modeling.
Candidates were reported to show fair knowledge of the concept. However, a good number of the candidates mixed up the types of data models with approaches to data modeling.