1. 3. REPRESENT
1.1. Data structures
1.2. Their characteristic
1.3. Relations
1.4. Constraints
1.5. Transformation
2. 2. MAIN FUNCTIONS
2.1. Help us understand the complexities of the real world
2.2. As a communication tools to facilitates the interaction among designer, programmer and user
3. 4. BASIC BUILDING BLOCKS
3.1. Entity
3.1.1. Anything or any real world object that can store data
3.2. Attribute
3.2.1. A characteristic of an entity
3.3. Relationship
3.3.1. Describe an association among entities
3.3.2. Types
3.3.2.1. 1:1
3.3.2.2. 1:M
3.3.2.3. M:N
3.4. Constraints
3.4.1. A restriction placed on the data
4. 7. DEGREES OF DATA ABSTRACTION
4.1. External model
4.1.1. End user's view of the data environment
4.1.2. DBMS dependant and both hardware and software independent
4.1.3. High level of abstraction
4.2. Conceptual model
4.2.1. Global view of the entire database
4.2.2. Independent of both software and hardware
4.2.3. Medium level of abstraction
4.2.4. Integrate all external view on a single view
4.3. Internal model
4.3.1. The database as seen by the DBMX
4.3.2. Software dependant and hardware independent
4.3.3. Maps the conceptual model to the DBMD
4.3.4. Medium level of abstration
4.4. Physical model
4.4.1. Describe the way data are saved on storage
4.4.2. Both software and hardware dependant
4.4.3. Operates at the lowest level of abstraction
4.4.4. Lowest level of abstraction
5. 1. DEFINITION
5.1. Model
5.1.1. An abstraction of a more complex real world object or event
5.2. Data model
5.2.1. Simple or graphical representation of complex real data structures
6. 6. BUSINESS RULES
6.1. A brief precise and unambiguous description of a policy / procedure / within a specific organizational environment
6.2. To define entity, attributes, relationsgip and constraint
6.3. Sources
6.3.1. Company manager
6.3.2. Department manager
6.3.3. Policy makers
6.3.4. Written document
6.3.4.1. Company procedures
6.3.4.2. Standard policy
6.3.4.3. Operation manual
6.3.5. End user
6.4. Importance
6.4.1. Help to standardise the company's view of data
6.4.2. To undersztand the business process
6.4.3. As a communication tools between user and designers
7. 5. EVOLUTION
7.1. Hierarchical model
7.1.1. Difficult to represent M:N relationships
7.1.2. Only set 1:M relationships
7.1.3. Represent by an upside down tree
7.2. Network model
7.2.1. Represent complex data relationships more effectively
7.2.2. Collection of records in 1:M relationships
7.3. Relational model
7.3.1. Conceptually simple
7.3.2. Set-oriented access
7.4. Entity-relationship model
7.4.1. Easy to understand
7.4.2. Limited to conceptual modelling
7.4.3. Widely accepted standard for data modelling
7.5. Object-oriented model
7.5.1. Basic for semantic data model
7.5.2. Models both data and relationships contained in a single structure known as an object