Four Types of Data Models
- 1. Data Models DEANNA MEDINA NORTHERN ARIZONA UNIVERSITY CIT311 ANALYSIS, DESIGN, & DATABASES: DATABASE THEORIES: ASSIGNMENT 1.1 JULY 24, 2017
- 2. Four Types of Data Models • Uses a collection of tables representing data and relationships Relational • Uses a collection of basic objects, called entities, and relationships between the entities Entity- Relationship • Combines the features of object-oriented and relational data models Object-Based • Allows for the specification of data where separate data items of the same type may have different sets of attributes Semi- Structured
- 3. Relational Data Models • Data and relationships are represented as tables containing columns with unique names. • Based on the concept of mathematical relations • The logical structure of the data model requires only that the database be perceived by the user as tables
- 4. Relational Schema • branchNo represents the primary key for the Branch table • branchNo is used as a foreign key in the Staff table to show the relationship between the two tables
- 5. Entity-Relationship Model • A type of Object-Based Model • Uses concepts of entities, attributes, and relationships
- 6. Entity-Relationship Diagram • Entities are represented as rectangles • Actions are represented by diamonds • Attributes are represented by ovals. • Connecting lines represent relationships
- 7. Object Based Model • Uses the concepts of entities, attributes, and relationships • Types of Object Based Models • Entity Relationship • Object-Oriented • Semantic • Functional
- 8. Object-Based Models USE RELATIONSHIPS BETWEEN TABLES AVOIDING DUPLICATION OF INFORMATION IN THE DATABASE
- 9. Semi-Structured Model • There is no separation between the data and the schema • A labled graph is used to represent data • There is no predefined schema
- 10. Semi-Structured Model http://www.dbinfoblog.com/post/126/semistructured-data-representation/ The graph to the left represents a semi-structured model for the movie StarWars and the actors/actresses that play in it.
- 11. References Connolly,T.M., & Begg,C.E. (2010). Database Systems: A Practical Approach to Design, Implementation, and Management (5th ed., pp. 1-14). Upper Saddle River, NJ: Addison-Wesley. Entity Relationship Diagram. (n.d.) Retrieved July 25, 2017 from https://www.smartdraw.com/entity- relationship-diagram/