Data Models in DBMS
Data models characterize how the legitimate structure of a database is displayed. Data Models are crucial entities to present abstraction in a DBMS. Data models define how data is associated with each other and how they are processed and stored inside the system.
Entity-Relationship (ER) Model depends on the idea of real-world entities and relationships among them. While drawing up the real-world scenario into the database model, the ER Model creates entity set, relationship set, general attributes and constraints.
Here I present some Data Models to make you understand that how we interpret the scenario and formulate it into a data model.
Scenario 1: We wish to track the level of various substances (for example, cholesterol or alcohol) in the blood of patients. For each blood sample that is taken from the patient, one test will be performed and the date of the sample, the substance tested, and the measured level of that substance will be recorded in a database.
Scenario 2: Enterprise Applications contain tens of data entry forms (pages) to capture business transactions. For Example Sales Order Form (page) is used to record sales orders received from customers. Similarly customer and supplier forms are used to maintain customers and suppliers respectively. Multiple users access the application. Users are granted access based on their rights. So some users can enter sales order or open new customer but cannot access supplier page.
Scenario 3: A library contains books and has a lot of members. Members get a book issued and then they return it after a specific period. Members can get one book issued at a time.