Phase 2 Entity Relationship Diagram (ERD) And Normalized Tab
Phase 2 Entity Relationship Diagram Erd And Normalized Tablesinstru
Phase 2: Entity Relationship Diagram (ERD) and Normalized Tables Instructions In this phase of the project you will determine the entities needed to support your project requirements outlined in Phase 1. Your deliverable for this phase will be: Entity Relationship Diagram (see Figure A-10 on page AC A-10) depicting entities and their underlying relationship. The final ERD will show entities and display their name, their attributes, primary keys, foreign keys, and relationship between entities. Display a list of tables in 3NF similar to the example on page AC A-20. This is a crucial step in your database design and if not done correctly the subsequent phases will not return the desired outcome.
Be sure to submit this on time and incorporate recommended changes. Copy and paste the class diagram to a Word document that also contains the list of tables in 3NF as described above.
Paper For Above instruction
In developing a robust and efficient database, the creation of an Entity Relationship Diagram (ERD) and the normalization of tables to the third normal form (3NF) are fundamental steps. The ERD serves as a visual representation of the data entities, their attributes, primary keys, foreign keys, and the relationships between entities. Normalization, on the other hand, ensures that the database tables are designed optimally to minimize redundancy, avoid undesirable characteristics such as update anomalies, and enhance data integrity.
The process begins with identifying all relevant entities that support the project requirements outlined in Phase 1. These entities could include items such as Customers, Orders, Products, Suppliers, and Employees, among others, depending on the specific application domain. Each entity’s attributes are then determined based on the data necessary for system operation. For example, a Customer entity might include CustomerID (primary key), Name, Address, Phone Number, and Email. The ERD visually depicts these entities with their attributes, highlighting primary keys (PK) and foreign keys (FK) that establish relationships between different entities.
Creating an accurate ERD involves understanding the relationships among entities, such as one-to-many, many-to-many, or one-to-one. For instance, a Customer can place many Orders, but each Order is associated with only one Customer, reflecting a one-to-many relationship. Similarly, a Product can be supplied by many Suppliers, indicating a many-to-many relationship that might require an associative entity to resolve in the physical database design.
After establishing the ERD, the next step is to translate this diagram into normalized tables. This involves converting the entities and their relationships into tables that are organized to conform to the Third Normal Form (3NF). Achieving 3NF requires that all non-primary key attributes are fully functionally dependent on the primary key, and there are no transitive dependencies (attributes dependent on other non-primary key attributes). These conditions help eliminate redundancy and ensure data consistency across the database.
For example, consider a table representing Orders. The table should include a primary key OrderID, and columns like CustomerID (foreign key), OrderDate, and TotalAmount. To conform to 3NF, data such as Customer address or contact details should reside in a separate Customer table, linked via CustomerID, instead of being duplicated within the Orders table. This structure facilitates easy data maintenance and minimizes anomaly risks.
To support the design process, detailed documentation should be prepared by listing all tables in 3NF with their primary keys, foreign keys, and attribute descriptions. This documentation acts as a blueprint for further development phases, including physical implementation and testing.
In summary, developing a clear ERD and well-normalized tables are critical steps that lay the foundation for a functional, efficient, and maintainable database system. Ensuring correctness at this stage influences the success of subsequent phases, making careful analysis, accurate diagramming, and thorough normalization essential practices for database developers.
References
- Coronel, C., & Morris, S. (2015). Database Systems: Design, Implementation, & Management. Cengage Learning.