Draw ERD Diagram using Draw.io скачать в хорошем качестве

Draw ERD Diagram using Draw.io

By the end of this activity, you will be able to design an Entity-Relationship Diagram (ERD) using the online editor draw.io and create corresponding tables in Oracle Database to model relationships between employees, departments, and skills. Explanation: In Oracle (or any relational database management system), entities and relationships are key concepts in database design. These concepts help structure and organize data efficiently while maintaining logical connections. Entities An entity represents a real-world object or concept that you want to store information about in the database. Entities are typically represented as tables in a database. Relationships A relationship represents how entities are connected to each other. In Oracle databases, relationships are typically modeled using foreign keys. Types of Relationships: 1. One-to-One (1:1): • One instance of Entity A is related to one instance of Entity B. • Example: An employee table and a department table, where each employee has exactly one department. 2. One-to-Many (1:N): • One instance of Entity A is related to multiple instances of Entity B. • Example: A Department table and an employee table, where each department has many employees. 3. Many-to-Many (M:N): • Multiple instances of Entity A are related to multiple instances of Entity B. • Example: An employee table and a Skill table, where each employee can have many skills, and each skill can have many employees.