Data Modelling and Data Flow Diagram

Question 1

A technique to document a software system using Entity Relationship Diagram (ERD)

Answer 1

Data Model

Question 2

Defines the possible number of occurrences in one entity

Answer 2

Cardinality

Question 3

Models the business objects that should exist in a system and the relationships between them.

Answer 3

Conceptual Data Model

Question 4

A detailed version of Conceptual ERD, Columns or attributes are defined, a new entity is added

Answer 4

Logical Data Model

Question 5

Actual Design blueprint of a relational database (Assign each key, column with type, length, nullable, etc.
)

Answer 5

Physical Data model

Question 6

Creating Data Flow Diagrams
STEPS:

Answer 6

1. Create a list of Activities
2. Construct Context Level DFD (identifies external entities and processes)
3. Construct Level 0 DFD (identifies manageable subprocess)
4. Construct Level 1 DFD (identifies actual data flows and data stores)
5. Check against rules of DFD