HI-600: Analysis and Design of Health Information Systems

Analysis: Part IVData Modeling: Entity Relationship Diagrams

Outline• The Entity Relationship Diagram (ERD)• Elements of ERD• The Data Dictionary and Metadata

• Creating an ERD• Validating an ERD• Normalization• CRUD Matrix

THE ENTITY-RELATIONSHIP DIAGRAM (ERD)

PATIENT PHYSICIANVISIT

Patient_Name

Patient_Sex

Patient_InsuranceID

Patient_DOB

*Physician_ID

Physician_Name

*Patient_ID

Physician_Speciality

Physician_BoardExamDate

*Patient_ID

*Physician_ID

Visit_Date

Visit_CopayAmount

Physician_Phone

Elements of an Entity Relationship Diagram

The Data Dictionary and Metadata

CREATING AN ENTITY RELATIONSHIP DIAGRAM

• Drawing the ERD is an iterative process of trial and revision.

• The basic steps in building an ERD:1. Identify the entities;2. add the appropriate attributes to each entity;

and3. draw relationships among entities.PATIENT PHYSICIANVISIT

Patient_Name

Patient_Sex

Patient_InsuranceID

Patient_DOB

*Physician_ID

Physician_Name

*Patient_ID

Physician_Speciality

Physician_BoardExamDate

*Patient_ID

*Physician_ID

Visit_Date

Visit_CopayAmount

Physician_Phone

goes to involves

Three special types of entities

• Independent Entity • Dependent Entity• Intersection Entity

PATIENT PHYSICIANVISIT

Patient_Name

Patient_Sex

Patient_InsuranceID

Patient_DOB

*Physician_ID

Physician_Name

*Patient_ID

Physician_Speciality

Physician_BoardExamDate

*Patient_ID

*Physician_ID

Visit_Date

Visit_CopayAmount

Physician_Phone

goes to involves

PATIENT PHYSICIAN

Patient_Name

Patient_Sex

Patient_InsuranceID

Patient_DOB

*Physician_ID

Physician_Name

*Patient_ID

Physician_Speciality

Physician_BoardExamDate

Physician_Phone

visits

ERD ExercisePatient ID Patient_Name Date_of_Birth Sex Insurance_ID

00211 Ross Schwimmer 12-15-2006 M 00464653 Marilyn Gustaf 04-17-2003 F 16534533 Obie Wan 05-05-1977 M 00438534 Mark McDonaldson 08-23-1959 M 13523522 Gurdy McMurdy 05-08-1965 U 313

Patient ID Physician ID Visit_ID Visit_Date00211 4324 890234 02-23-200764653 2376 890235 02-24-200734533 5656 890236 06-18-200738534 3453 890237 09-12-200700211 4324 890238 01-12-200864653 2376 890239 06-21-200834533 4324 890240 12-12-200838534 3453 890241 01-03-200934533 4324 890242 08-09-200938534 4324 890243 01-01-2010

Physician ID Physician_Name4324 Dr. Clark Griswald2376 Dr. Ellen Dewer5656 Dr. Jack Ryan2314 Dr. Pat Goody7954 Dr. Motley Feelgood3453 Dr. Krista Congle

PATIENT PHYSICIANVISIT

Patient_Name

Patient_Sex

Patient_InsuranceID

Patient_DOB

*Physician_ID

Physician_Name

*Patient_ID

Physician_Speciality

Physician_BoardExamDate

Patient_ID

Physician_ID

Visit_Date

Visit_CopayAmount

Physician_Phone

*Visit_ID

goes to involves

VALIDATING AN ERD• General design guidelines• Normalization• Check the ERD against the process models

to make sure that both model balance each other

Design Guidelines

Normalization

Normalization: 1NFDo any attributes have multiple values for a single instance of an entity?

Normalization: 2NFIf the identifier is composed of more than one attribute, are any attribute values dependent on just part of the identifier?

Normalization: 3NFDo any attribute values depend on an identifier that is not the entity’s identifier?

Balancing ERDs with DFDs

SUMMARY• Basic Entity Relationship Diagram Syntax• Entity describes people, places, or things.• Attribute is some type of information about the entity.• Relationship conveys the associations between entities.

• Creating an ERD• Identify the entities.• Add the attributes to each entity.• Draw relationships among entities.

• Validating an ERD• Normalization• CRUD matrix