Team 4SPRING 2004

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Mountain View Community Hospital Case Installment
Four George Hannah, Brian Horn, Sheri Walls
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Who is MVCH?
Mountain View Community Hospital is a 150-bed,
not-for-profit, short-term, acute care general
hospital. The main concern of MVCH is to provide
high-quality health care for its surrounding
community while containing costs that have been
rising in accordance with national trends in
recent years. MVCH is in the process of
developing a high-level E-R diagram for the
hospital. Interviews with hospital staff and
administration have been conducted and our
development team of three persons has identified
the key entity types for the hospital and mapped
out the relationships on paper. Following are
questions that we asked, answers to those
questions, and findings from our meetings.
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Question 1
Is the ability to model supertype/subtype
relationships likely to be important in a
hospital environment such as Mountain View
Community Hospital? Why or why not?

• Yes, the ability to model supertype/subtype
  relationships is likely to be very important for
  MVCH. A modern hospital is a triumph of
  specialization. Many hospital entities are likely
  to have subtypes, for example
• ITEM possible subtypes are Supply Item
  Prescription Item
• PATIENT possible subtypes are Inpatient
  Outpatient
• TEST possible subtypes are Scan Blood test
• PROCEDURE possible subtypes are Biopsy Surgical

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Question 2
Can the business rules paradigm and the ability
to easily define, implement, and maintain
business rules be used as a competitive advantage
in a hospital environment such as MVCH? Why or
why not?
Yes, the business rules paradigm can be used for
competitive advantage. Business rules allow a
business to change its processes and procedures
quickly in responding to environmental changes.
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Question 3
Yes, the entity VISIT (scheduled for outpatients)
is clearly a weak entity.
Do there appear to be any weak entities in the
description of the data requirements in this
project segment? If so, what are they?
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Question 4

• A hospital has many business rules. Two examples
  not mentioned in this case are
• A patient cannot be admitted to the hospital
  without a referral from a responsible physician.
• A nurse can be reassigned to a different care
  center only by permission of the nurse in charge
  of the care center where the nurse is presently
  assigned.

Can you think of any business rules (other than
the one explicitly described in the case) that
are likely to be used in a hospital environment?
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Exercise 1
Draw an EER diagram to accurately represent this
set of requirements, carefully following the
notation from this chapter.
See handout diagram 1
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Exercise 2

• Develop definitions for each of the following
  types of objects in your EER diagram from Project
  Exercise 1. Consult with some member of the
  hospital or health care community if one is
  available otherwise make reasonable assumptions
  based on your own knowledge and experience.
• Entity types
• Attributes
• Relationships

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Exercise 2 Answer

• Entity Type Definitions
• Physician a licensed professional health-care
  provider associated with MVCH
• Patient a person that has come to MVCH for
  health care whether inpatient or outpatient
• Employee someone who performs some task for
  MVCH in return for compensation this person is
  on MVCHs payroll and not to be confused with a
  consultant or contractor
• Care Center an organizational unit that
  performs a related set of services directed
  toward patient care.
• Attribute Definitions
• Person_ID - a unique identifier of patients such
  as a social security number
• Birth_Date the date that a patient was born
  expressed as month/day/year.
• Specialty the primary emphasis area of practice
  for a physician or department
• Location the physical and/or logical place
  where a specific function is performed by MVCH
• Relationship Definitions
• Assigned associates an in-patient with a bed
• Scheduled associates an outpatient with an
  instance of a visit to MVCH

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Exercise 3

• You should recognize the statement a nurse
  cannot be appointed nurse_in_charge of a care
  center unless she or he has an RN certificate as
  a statement of a business rule. Answer the
  following questions
• What is the anchor object? Is it an entity, an
  attribute, a relationship, or some other object?
• What is the corresponding object (or object)? Is
  it an entity, attribute, relationship or other
  type of object?

• Anchor object Nurse (entity)
• Corresponding object RN Certificate (attribute
  with specific value)

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Exercise 4
The EER diagram places some entities, that were
separate in the E-R diagram, under the same
classification. There are differences because the
EER diagram shows supertype/subtype relationships
and the E-R diagram only shows each subtype
standing alone with their own attributes.
Compare the EER diagram that you developed in
this chapter with the E-R diagram from Chapter 3,
Exercise 2. What are the differences between
these two diagrams? Why are there differences?
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Exercise 5
Merge the two diagrams from Exercise 4 above and
Exercise 2 in Chapter 3 into a single diagram.
Explain decisions you make during the merging.
See handout diagram 2
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Georges Question
What are some examples of partial specialization
and total specialization in the EER diagrams in
Exercise 5?
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Georges Answer
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Brians Question
Could MVCH display a supertype/subtype
relationship with the entity ITEM?
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Brians Answer
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Sheris Question

• In what ways could MVCH use an internet-searchable
  database to help provide service to its
  customers?

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Sheris Answer
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Conclusion
By diagramming its supertypes and subtypes, MVCH
can better analyze how its different entities are
related, thus making planning easier and more
efficient.