When you’re talking about tables, columns, and foreign keys in the context of a database, you are typically modeling both a relational model and a logical model, and there is a distinction between the two:
- Relational Model:
- The relational model is a theoretical framework for organizing data in a structured way. It was first proposed by Edgar F. Codd in the 1970s. The core concept of the relational model is the use of tables (relations) to represent data, where each table consists of rows (tuples) and columns (attributes).
- In the relational model, the emphasis is on the mathematical and theoretical aspects of data organization. It defines the fundamental concepts like relations, attributes, and keys.
- Logical Model:
- The logical model, on the other hand, is a practical representation of the relational model tailored to a specific database management system (DBMS) and its implementation. It involves designing database tables, defining columns, specifying data types, and establishing relationships between tables using foreign keys.
- The logical model takes into account the physical constraints of a particular DBMS, performance considerations, and other real-world aspects that the relational model doesn’t address.
- The logical model is the blueprint for how data will be structured and stored in a specific database system. It includes the creation of tables, indexes, views, and the establishment of constraints like foreign keys.
In summary, the relational model is a theoretical framework that defines the fundamental concepts of how data should be organized in tables, while the logical model is a practical implementation of the relational model tailored to a specific database system. The logical model translates the abstract concepts of the relational model into concrete structures and relationships that are used to store and manage data in a DBMS.