LU03 - RDB: concept & notation

Relational databases are fundamental to modern data management, offering a structured approach to storing and accessing data. The design of a relational database begins with conceptualizing the data and its relationships, forming the logical schema that represents real-world entities and their interactions within a system.

Data types are essential in this design process. They define how data is stored, classified, and processed, with common types including integers, strings, and dates. Correct data type selection ensures efficiency, data integrity, and optimized query performance.

Entity-Relationship Models (ERM) and Entity-Relationship Diagrams (ERD) are key tools in database design. The ERM outlines entities and their relationships, while the ERD provides a visual representation of this model. Entities represent objects or concepts, like customers or orders, and relationships illustrate how these entities interact within the system.

Crow’s foot notation, commonly used in ERDs, helps depict the cardinality of relationships—whether they are one-to-one, one-to-many, or many-to-many. This notation is crucial for clearly defining how entities connect, ensuring the database accurately reflects the intended data structure.

• LU03.A03: ERM: travel_db - voluntary exercise - in due time
• LU03.A04: ERM: university_db - voluntary exercise - in due time
• LU03.A05: ERM: webshop_db - voluntary exercise - in due time
• LU03.A06: ERM: hobby_db - voluntary exercise - in due time

• LU03.L03: ERM: travel_db - voluntary exercise - in due time
• LU03.L04: ERM: university_db - voluntary exercise - in due time
• LU03.L05: ERM: webshop_db - voluntary exercise - in due time
• LU03.L06: ERM: hobby_db - voluntary exercise - in due time

Volkan Demir