ER Diagram for Hospital Management System

Introduction

• Learning to draw the ER diagram for a hospital management system.

Step 1: Choose Entities

• Entity Definition: An object with physical or conceptual existence.
• Entities Identified:
  • Doctor: Physically existing entity.
  • Patient: Physically existing entity.
  • Medicine: Conceptually existing entity.
• Rectangular Boxes: Entities are represented inside rectangular boxes.
  • Draw three rectangular boxes:
    1. Doctor
    2. Patient
    3. Medicine

Step 2: Write Attributes Associated with Entities

• Attribute Definition: Characteristics of an entity.
• Attributes Representation: Attributes are written inside ovals.

Attributes for Doctor

• Name: Composite attribute (can be divided into first name, middle name, last name).
• Doctor ID: Primary key (uniquely identifies a doctor; underlined).
• Address: Basic attribute.
• Phone Number: Multi-valued attribute (can have multiple phone numbers; represented in double oval).

Attributes for Patient

• Name: Composite attribute (can be divided into first name, middle name, last name).
• Patient ID: Primary key (uniquely identifies a patient; underlined).
• Address: Basic attribute.
• Phone Number: Multi-valued attribute (can have multiple phone numbers; represented in double oval).

Attributes for Medicine

• Quantity: Amount of medicine available.
• Price: Cost of the medicine.

Step 3: Join Entities Using Relationships

• Relationship Definition: Represents interaction between entities, drawn as diamond shapes.
• Relationships Identified:
  • Doctor - Patient: Relationship is labeled as "treats" (Doctor treats Patient).
  • Patient - Medicine: Implies that after treatment, the Patient buys Medicine and pays the bill.

Conclusion

• Diagram Summary:

  • Entities: Doctor, Patient, Medicine.
  • Attributes: Various attributes defined for each entity.
  • Relationships: Connections between entities represented by diamonds.

• This concludes the ER diagram for the hospital management system.

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