1
|
- Database Design 2:
- Design Methodology
|
2
|
- Discuss the general process and goals of database design
- Define user views and explain their function
- Define database design language and use it to document database designs
- Create an entity-relationship diagram to visually represent a database
design
- Present a methodology for database design at the information level and
view examples illustrating this methodology
|
3
|
- Explain the physical-level design process
- Examine some alternative approaches to entity-relationship diagrams
- Discuss top-down and bottom-up approaches to database design and examine
the advantages and disadvantages of both methods
- Use a survey form to obtain information from users prior to beginning
the database design process
|
4
|
- User Views
- Requirements necessary to support a particular user’s operations
|
5
|
|
6
|
- Represent all keys
- Primary, alternate, secondary, foreign
- Database Design Language (DBDL)
- Mechanism for representing tables and keys
- Table name followed by columns in parentheses
- Primary key column(s) underlined
- AK identifies alternate keys
- SK identifies secondary keys
- FK identifies foreign keys
|
7
|
|
8
|
|
9
|
- Undertaken after information-level design completion
- Most DBMSs support primary, candidate, secondary, and foreign keys
- DB programmers must include logic to ensure the uniqueness of primary
keys and enforce other conditions
|
10
|
|
11
|
|
12
|
|
13
|
|
14
|
|
15
|
- Bottom-up
- Design starts at low level
- Specific user requirements drive design process
- Top-down
- Begins with general database that models overall enterprise
- Refines the model until design is achieved
|
16
|
- Used to collect information from users
- Must contain particular elements
- Entity information
- Attribute information
- Relationships
- Functional dependencies
- Processing information
|
17
|
- Aid in collecting user requirements
- Collect information similar to that collected with survey forms
- Entity information
- Attribute information
- Relationships
- Functional dependencies
- Processing information
|
18
|
|
19
|
|
20
|
|
21
|
|
22
|
|
23
|
|
24
|
|
25
|
|
26
|
|
27
|
|
28
|
|
29
|
|