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Using High-Level, Conceptual Data Models for Database Design Entity-Relationship (ER) model •Popular high-level conceptual data model ER diagrams •Diagrammatic notation associated with the ER model 2
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In this article, we will explore various ER diagram examples with solutions in PDF format. These examples cover a range of scenarios and demonstrate how ER diagrams can be used to design and represent complex database structures.
- Lecture 7
- Comprehensive
- Concise/High-level
- Algorithmically Transformable
- Set of entities that have the same attributes
- CAR
- DEPARTMENT
- PROJECT
- DEPT
- FACULTY
- STUDENT
- DEPT
- STUDENT
- DEPT
- is important)
- Tutee
- >N, can go to (1) entity
Context Design & Implementation Process Goals of Conceptual Design Entity-Relationship (ER) Model One ER Diagrammatic Notation Requirements Elicitation Approaches to Conceptual Design
Entity types, relationships, and constraints Sanity check of data & functional requirements Reference for [unit/integration] testing/analysis
Easy to understand technically Easy to communicate with non-technical users Facilitates focus on data (vs. storage/implementation details)
• Improves application development efficiency, reduces errors Entity • Thing in the real world Attribute Property of an entity Most of what we store in the database Relationship Association between sets of entities Possibly with attribute(s) Graphical depiction of an ER model Many notations, this class... All cars have a year, age, make, model, reg...
Make Year Model All cars have a year, make, and model.
Can be subdivided into smaller subparts All cars have a year, make, model, and registration. Can take a [possibly specified] number of values. All cars have a year, make, model, registration, and some number of colors. Make Year Model Color CAR Registration State Number The value uniquely identifies each entity All cars have a year, make, model, re...
Manager Manager_ Start_Date Draw an ERD for the following description: A department controls a number of projects, each of which has a unique name, a unique number, and a single location. Location Name Number
Controlling_ Department Draw an ERD for the following description: We store each employee’s name (first, last, MI), Social Security number (SSN), street address, salary, sex (gender), and birth date. An employee is assigned to one department, but may work on several projects, which are not necessarily controlled by the same department. We keep trac...
CHAIR_F All departments have a faculty member who serves as the chair. A faculty member can only chair one
department. Associates one or more sets of entities
All students must have a department in which they major.
CHAIR_F FACULTY Associates one or more sets of entities
MINOR_D Students may have any number of departments in which they minor.
CHAIR_F FACULTY Associates one or more sets of entities – One = recursive (role
MAJOR_D Constrains the number of entities that can participate in each role of the relationship Tutor
All departments have a faculty member who serves as the chair. A faculty member can only chair one department. Constrains the number of entities that can participate in each role of the relationship Constrains the number of entities that can participate in each role of the relationship Constrains the number of entities that can participate in each ...
N MAJOR_D STUDENT N MINOR_D Tutor N Tutee M TUTORS Each department chair has an office. Office
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Dec 21, 2023 · What is an Entity Relationship Diagram (ERD)? An Entity Relationship Diagram (ERD) is a type of diagram that lets you see how different entities (e.g. people, customers, or other objects) relate to each other in an application or a database.
What is an ER diagram? An Entity Relationship (ER) Diagram is a type of flowchart that illustrates how “entities” such as people, objects or concepts relate to each other within a system. ER Diagrams are most often used to design or debug relational databases in the fields of software engineering,
Dive into the realm of database visualization. Unlock the world of ER diagrams with this collection of 20 easy-to-follow ER diagram examples and templates.
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Examples are a person, car, customer, product, gene, book etc. Attributes: an entity is represented by a set of attributes (its descriptive properties), e.g., name, age, salary, price etc. Attribute values that describe each entity become a major part of the data eventually stored in a database.
