Rob & Coronell - Chapter 2 Flashcards
What is the focus of database design?
How the database structure will be used to store and manage end-user data
What is data modeling?
The first step in designing a database
The process of creating a specific data model for a determined problem domain.
What is a data model?
A simple representation of a complex real-world object or event.
Goal: The help understand the real-world object or event.
- Or a simple representation of a data structure and its relationships.
What is meant by data modeling is an iterative, progressive process?
You start with a simple understanding of the problem domain, and as your understanding of the problem domain increases, so does the level of detail of the data model.
The end product is a blueprint, containing all instructuctions to build the database
When is a data model correct?
When it meets all the end-users requirement.
- There can be more than one solution
- It is trial and error
What do data models facilitate?
Interaction among the designer, the applications programmer and the end user.
Why is data modelling so important?
Data constitute the most basic information units employed by a system. Data is viewed in different ways (and different importance) by the different end-users. When a good database blueprint is available, it does not matter that an application programmer’s view of the data is different from others.
What are the basic building blocks of all data models?
- Entities
- Attributes
- Relationships
- Constraints
What is an entity?
Anything about which data are to be collected and stored. Think about a person, place, thing or event.
What is an attribute?
A characteristic of an entity.
What is a relationship?
It describes the association among entities
Which relationships are there?
- One-to-Many (1:M )
- Many-to-Many (M:N)
- One-to-one (1:1)
What is a constraint?
A restriction placed on data. They help ensure data integrity.
