Database modeling is the process of creating a conceptual model that defines the logical structure of a database. This model specifies the entities (tables), the attributes (columns) and the relationships between these entities. There are three main types of database model: conceptual, logical and physical. ### <br>Conceptual model Aims to represent the basic structure of the database, identifying the main entities and their relationships. - Components: Entities (such as customers, products) and relationships (for example, "a customer can place many orders"). - Tools: Entity-Relationship Diagrams (ERD). ### <br>Logical model Refine the conceptual model, including details such as entity attributes and primary and foreign keys. - Components: Tables, columns, primary keys (PK) and foreign keys (FK). - Tools: Normalization to avoid redundancies and inconsistencies. ### <br>Physical model - Implement the logical model in the specific database management system (DBMS). - Components: Data types, indexes, physical tables, triggers, and stored procedures. #<br>Example: Hotel Reservation System ### <br>Conceptual Model: 1-Entities: - Guest - Room - Reservation 2-Relationships: - A Guest can make several Reservations. - A Room can be associated with several Reservations. ### <br>Logical Model: 1-Tables: + Guest (id, name, email) + Room (id, type, capacity) + Reservation (id, guest_id, room_id, date_checkin, date_checkout) 2-Relationships: + Guest.id -> Reservation.guest_id (foreign key) + Room.id -> Reservation.room_id (foreign key) ### <br>Physical Model: 1-Data Types: + Guest: id (int, PK), name (varchar), email (varchar) + Room: id (int, PK), type (varchar), capacity (int) + Reservation: id (int, PK), host_id (int, FK), room_id (int, FK), date_checkin (date), date_checkout (date) 2-Indexes and Optimizations: + Indexes on the host_id and room_id fields to improve query performance. Good database modeling is essential to ensure an efficient, flexible system that meets business needs. You can access more content related to Databases by clicking on this [link](https://chat-to.dev/search?p=sql).