2-1. Define each of the following terms: entity type entity-relationship model entity instance attribute relationship type strong entity type multivalued attribute associative entity cardinality constraint weak entity identifying relationship derived attribute business rule
Added by Gema W.
Step 1
Entity type: A category of objects or things that have common characteristics and can be identified uniquely. For example, "customer" can be an entity type in a database. Show more…
Show all steps
Your feedback will help us improve your experience
Danielle Ashley and 91 other AP CS educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
Supreeta N.
Mini Final Project Part 1: Due [6/23/2020] 1. Select a topic to design. 2. Design ER Diagram. 3. Define Entity-Relationship schema. Marking Scheme: ER Diagram i. Is the ER Diagram clear? Yes No ii. Match the style from class? Yes No iii. Is the cardinality accurate? Yes No iv. Match the structure from the DDL scripts? Yes No v. Missing Relationships? Yes vi. Does the ER Diagram have Many-Many Relationships? Yes No vii. Is the diagram in the Third Normal Form? Yes No Comments: No Minimum Requirements: - 4 Entities - Minimum of 4 Attributes per Entity - Each table must include a primary key - Database must use a minimum of 3 foreign keys
Akash M.
Given the E-R diagram on the following page, list the names of the entities, attributes, keys, and relationships being used. 2. For each entity, give a formal written description, including all of its attributes and its key. 3. For each relationship, give a formal written description of both directions of the relationship, including its cardinality.
Recommended Textbooks
Computer Science and Information Technology
Introduction to Programming Using Python
Computer Science - An Overview
Watch the video solution with this free unlock.
EMAIL
PASSWORD