Analysis - Data Modelling Flashcards
Data Modelling
1
Q
How does a data model develop over time?
A
- The data model is drawn by an iterative process in which the model becomes more detailed and less conceptual over time.
1
Q
What is a data model?
A
- A data model is a formal way of representing the data that are used and created by a business system; it illustrates people, places, or things about which information is captured and how they are related to each other.
2
Q
How is a data model used in the analysis phase?
A
- During analysis, analysts draw a logical data model, which shows the logical organization of data without indicating how data are stored, created, or manipulated
3
Q
How is a data model used in the design phase?
A
- In the design phase, analysts draw a physical data model to reflect how the data will physically be stored in a databases and files.
4
Q
How is a data model used in the design phase later on?
A
- Later, during the design phase, the data model is changed to reflect exactly how the data will be stored in databases and files.
5
Q
What does ERD stand for?
A
Entity relationship diagram
6
Q
What is an entity relationship diagram?
A
- An entity relationship diagram (ERD) is a picture which shows the information that is created, stored, and used by a business system.
- On an ERD, similar kinds of information are listed together and placed inside boxes called entities.
- Lines are drawn between entities to represent relationships among the data
- Special symbols are added to the diagram to communicate high-level business rules that need to be supported by the system.
- The ERD implies no order, although entities that are related to each other are usually placed close together.
7
Q
How can an analyst use an entity relationship diagram?
A
An analyst can read an ERD to discover the individual pieces of information in a system and how they are organized and related to each other.