Fig. 4

The Entity-Relationship (ER) of the Relational Database Management System (RDMS) in the RS-DBS. An ER diagram is a visual model used in database design. It represents the entities and their relationships within a database in a graphical manner. In this ER diagram, the detailed items within each table are hidden to facilitate a clear representation of the relationships between the tables. Only the primary keys are shown to focus on the main structure and connections of tables in the RDMS. The Sample ID in the Sample Data Table is the primary key. It has a one-to-many relationship with other tables in the sample with the Sample File Data Table, each Measurement Data Table, and the Sample Loan Data Table. A Measurement ID in each Measurement Data Table is the primary key item and has a one-to-one relationship with each subordinate Measurement File Data Table. The Sample Loan ID in the Sample Loan Data Table is the primary key item and has a one-to-one relationship with the Sample Loan File Data Table