Database Design Activities
Activity
1)
2)
Identify the entities and attributes based
upon the excerpt from an interview of the
manager of an appliance repair shop
described on the next several slides.
Create the resulting tables.
2
Activity (cont’d)
“We’re in a bit of trouble here. This is the third week in a row that we have lost a
customer’s TV set. Somehow we’ve got to keep better track of who brought in
which appliance, and when. And when the appliance is picked up by the
customer. We also need to know which of our technicians worked on which
appliance, and how long it took.
We are also having problems with repair equipment loss. Some equipment has
gone missing and I’m afraid it is due to employee theft. The equipment is
numbered but we can never remember where we put it. We need to have each
employee check each piece out when he needs it, and check it back in when he’s
done with it – and only one piece at a time. That way the last guy to check it out
pays for it if it’s missing.
As you can see this is a big shop and each technician is assigned
to a bench but I can’t keep track of which employee is assigned
to which bench. Sometimes I wish we hadn’t gotten so big…
3
Activity (cont’d)
I had this idea – we’d stamp each appliance the customer brought in, with a
number. Then we’d put it on the shelf, and when a technician needed work he’d
go to the shelf and sign it out. That way, we’d know who had it last. If the
technician can’t fix it, he’d put it back and sign it back in. But only after he wrote
down how long he had worked on it.
Well it was a great idea. I had these cards printed up and everybody wrote all the
information on the card and it worked great. Then we ran out of cards and the
print shop was closed and the system fell apart.
Here’s another problem – the other day a customer walked in with a whole pile of
appliances – TVs, radios, a microwave, - you name it. We had to write his name
and phone number on 15 of those little slips. And along the same lines – there
was a customer who came in the same day who got rather agitated when she had
to give her
name and phone number. She seemed to think we should have
remembered it because she was just in a week before.
So you can see we have some major problems and we hope
you can design a better system for us.”
4
Activity
1)
Draw a simple ERD containing the Order, Customer, and
Product entities. Show attributes and PKs and FKs.
2)
Choose appropriate relationship names using your
common knowledge of interactions between
customers, products and orders.
3)
Extend the ERD to include the Employee entity.
4)
Choose appropriate relationship names using your
common knowledge of interactions between
employees and orders.
5)
The next slide describes the attributes for each entity.
5
Activity (cont’d)
•
Customer attributes:
CustNo , CustFirstName, CustLastName,, CustStreet,
CustCity, CustState, CustZip, CustBal (balance.)
•
Order attributes:
OrdNo, OrdDate, OrdName, OrdStreet, OrdCity, OrdState, OrdZip.
•
Product attributes:
ProdNo, ProdName, ProdQOH, ProdPrice, ProdNextShipDate.
•
Employee attributes:
EmpNo, EmpFirstName, EmpLastName, EmpPhone,
EmpEmail, EmpCommRate (commission rate),
EmpDeptName.
6
Activity
Define an ERD for database for managing the task
assignments on a work order.
 A work order records the set of tasks requested by a customer
at a specified location.
 A customer has a unique customer identifier, a name, and a
billing address (street, city, state, zip).

A work order has a unique work order number, creation date, date required, a
completion date, an optional supervising employee, a work address (street,
city, state, zip), and a set of tasks.
 Each task has a unique task identifier, a task name, an hourly rate, and
estimated hours. Tasks are standardized across work orders so that the same
task may be performed on many work orders.
 Each task on a work order has a status (not started, in progress, or
completed), actual hours, and a completion date. The completion date is not
entered until the status changes to complete.
 A work order cannot be created unless at least 1 task is known.
7
Normalization Exercise
•
For the following description of a database to support physical plant operations,
identify functional dependencies and construct normalized tables. Using the
simple synthesis procedure, design a collection of tables in 3NF.
•
Design a database to assist physical plant personnel in managing key cards for
access to buildings and rooms. The primary purpose of the database is to ensure
proper accounting for all key cards.
8
Room Key Normalization Exercise
•
A building has a unique building number, a unique name, and a location within the
campus.
•
A room has a unique room number, a size (physical dimensions), a capacity, a number
of entrances, and a description of equipment in the room. Each room is located in
exactly one building. The room number includes a building identification and
followed by an integer number. For example, room number KC100 identifies room
100 in the King Center (KC) building.
•
An employee has a unique employee number, a name, a position, a unique email
address, a phone, and an optional room number in which the employee works.
•
Magnetically encoded key cards are designed to open one or more rooms. A key card
has a unique card number, a date encoded, a list of room numbers that the key card
opens, and the number of the employee authorizing the key card. A room my have
one or more key cards that open it.
•
A key type must be authorized before it is created.
9
ERD Activity: Seminar Registration System
Recall our work with the proposed new online system to automate seminar registration for
a company that offers seminars at multiple sites and on multiple dates. Here are some
features of the proposed system that were gathered at an initial one-hour meeting
with the customer.
1.
Seminar registration is now handled by mail or by phone, based on seminar
brochures sent out in the mail. The customer wishes to implement an online (webbased) enrollment system.
2.
A potential seminar enrollee should be able to go the new web site, select a specific
seminar and then pay for and enroll in it if space is available.
3.
Payment would be made by an online credit card transaction.
4.
Currently all seminar information (title, instructor, location, date, time, current
enrollment, and maximum enrollment allowed) is held in a Excel spreadsheet.
5.
A separate Excel spreadsheet contains some information (name, address, phone,
email, credit card info) about previous seminar attendees.
6.
The seminar manager requested a new daily report showing the current status of
enrollment for all seminars.
10
ERD Activity: Seminar Registration System
Recall that we refined the initial set of objectives given to us by the customer
by identifying the underlying primary business needs, and by constructing and
refining a Level 0 DFD for the proposed system, which is reproduced on the
next slide.
In this activity, using the Level 0 DFD and the understanding that we have
gained about the proposed system, to create an Entity Relationship Diagram
(ERD) that models the major entities and their relationships (including
cardinalities).
Once you complete the ERD, identify (or create) primary keys for each entity,
and decide what foreign keys will be required to connect the various entities.
Finally, identify additional attributes that would be important to store for each
entity.
11
Level 0 DFD
Attendee Info*
seminar_cancellation
Email Sys
seminar_cancelled
Class Admin
registration_decline
confirmation_of_cancellation
request_for_transcript
catalog_search_req
Seminar
Attendee
registration_req_w_cc
registration_req_w_corp_pmt
payment_info
Proposed
System
credit
action
Corporate
Financial System
cancellation
confirmation_of_seat
confirmation_of_cc_pmt
transcript
Seminar Mgr
certificate
search_results
Seminar Info*
* Customer will convert current data
Activity
For the following tables of a financial planning database,
identify possible uses of denormalization and derived
data to improve performance. In addition, identify
denormalization and derived data already appearing in
the tables.
The tables track financial assets held and trades made by customers. A
trade involves a purchase or sale of a specified quantity of an asset by
a customer. Assets include stocks and bonds. The Holding table
contains the net quantity of each asset held by a customer. For
example, if a customer has purchased 10,000 shares of IBM and sold
4,000, the Holding table shows a net quantity of 6,000. A frequent query
is to list the most recent valuation for each asset held by a customer.
The most recent valuation is the net quantity of the asset times the most
recent price.
Activity continued
 Customer(CustNo, CustName, CustAddress, CustCity, CustState, CustZip,
CustPhone)
 Asset(AssetNo, SecName, LastClose)
 Stock(AssetNo, OutShares, IssShares)
 Bond(AssetNo, BondRating, FacValue)
 PriceHistory(AssetNo, PHistDate, PHistPrice)

FOREIGN KEY AssetNo REFERENCES Asset
 Holding(CustNo, AssetNo, NetQty)

FOREIGN KEY CustNo REFERENCES Customer

FOREIGN KEY AssetNo REFERENCES Asset
 Trade(TradeNo, CustNo, AssetNo, TrdQty, TrdPrice, TrdDate, TrdType, TrdStatus)

FOREIGN KEY CustNo REFERENCES Customer

FOREIGN KEY AssetNo REFERENCES Asset
Customer Database for Municipal Water Utility
•
The database should support recording of water usage and billing for water usage.
To support these functions, the database should contain data about customers,
rates, water usage, and bills. Other functions such as payment processing and
customer service are omitted from this description for brevity. The following list
describes the data requirements in more detail.
•
Customer data include a unique customer number, a name, a billing address, a
type (commercial or residential), an applicable rate, and a collection (one or more)
of meters.
•
Meter data include a unique meter number, and address, a size, and a model. A
meter is associated with one customer at a time.
•
An employee periodically reads each meter on a scheduled date. When a meter is
read, a meter-reading document is created containing a unique meter reading
number, and employee number, a meter number, a time stamp (includes date and
time), and a consumption level. When a meter is first placed in service, there are
no associated readings for it.
15
Customer Database for Municipal Water Utility
•
A rate includes a unique rate code, a description, a fixed dollar amount, a
consumption threshold, and a variable amount (dollars per cubic foot).
Consumption up to the threshold is billed at the fixed amount. Consumption
greater than the threshold is billed at the variable amount. Customers are assigned
rates using a number of factors such as customer type, address, and adjustment
factors. Many customers can be assigned the same rate. Rates are typically
proposed months before approved and associated with customers.
•
The water utility bills are based on customers’ most recent meter readings and
applicable rates. A bill consists of a heading part and a list of detail lines. The
heading part contains a customer number a preparation date, a payment due date,
a date range for the consumption period. Each detail line contains a meter
number, a water consumption level, and an amount. The water consumption level
is computed by subtracting the consumption levels in the two most recent meter
readings. The amount is computed by multiplying the consumption level by the
customer’s rate.
16
CAPSTONE Activity 1
Define an ERD for the following narrative.
2) Show the attributes and the PKs and FKs.
3) Refine the ERD with a generalization
hierarchy to depict similarities between
buyers and owners.
4) Strive for 3NF
1)
17
CAPSTONE Activity (cont’d)
•
The database tracks homes, owners, buyers, agents and buyer offers made.
•
A home has a unique home identifier, a street address, a city, a state, a zip, a number
of bedrooms, bathrooms, and square feet. A home is either owner occupied or
rented. An owner has a social security number, a name, an optional spouse name, a
profession, and an optional spouse profession. An owner can possess one or more
homes. Each home has only one owner.
•
Agents represent owners. An agent can list many homes but only one agent can list a
home. An agent has a unique agent identifier, a name, an office identifier, and a
phone number. An office may have more than one agent working in the office. When
an owner agrees to list a home with an agent, a commission (percentage of the sales
price) and a selling price are determined.
•
A buyer has a social security number, a name, a phone, preferences for the number of
bedrooms and bathrooms, and a price range. An agent can work with many buyers,
but a buyer works with only one agent.
•
A buyer makes an offer on a home for a specified sales price. The offer starts on the
submission date and time and expires on the specified date and time. A unique offer
number identifies an offer. A buyer may submit multiple offers for the same home.
18
CAPSTONE Activity 2
1.
2.
3.
Define an ERD for the narrative on the following slide.
Show the attributes and the PKs and FKs.
Refine your ERD to add a generalization hierarchy to
distinguish between nurse and physician providers. A
nurse has a pay grade and a title. A physician has a
residence hospital, email address, and a certification.
The other attributes of provider apply to both
physicians and nurses. A visit involves a physician
provider while a visit detail may involve a nurse
provider.
Strive for 3NF.
19
CAPSTONE Activity 2 (cont’d)
•
A patient may be treated by one or more health care providers through a visit.
Patient information includes name, address, phone and health plan.
•
A health care provider has a unique provider number, a first name, a last name, a
phone, a specialty, a hospital name in which the provide practices, an email
address, a certification, a pay grade, and a title. A provider is required for a patient
visit. New providers do not have associated visits.
•
A visit includes a visit number, visit date, visit pay method, and charge for the visit.
•
A visit detail includes a detail number, a detail charge, an optional provider
number, an item number. The combination of the visit number and visit detail
number is unique for a visit detail. An item includes a unique item number, an item
description, an item price, and an item type. An item can be related to multiple
visits. New items may not be related to any visit details. A provider can be related
to multiple visit details. Some providers may not be associated to any visit details.
20
ERD Activity: Seminar Registration System
Recall our work with the proposed new online system to automate seminar registration for
a company that offers seminars at multiple sites and on multiple dates. Here are some
features of the proposed system that were gathered at an initial one-hour meeting
with the customer.
1.
Seminar registration is now handled by mail or by phone, based on seminar
brochures sent out in the mail. The customer wishes to implement an online (webbased) enrollment system.
2.
A potential seminar enrollee should be able to go the new web site, select a specific
seminar and then pay for and enroll in it if space is available.
3.
Payment would be made by an online credit card transaction.
4.
Currently all seminar information (title, instructor, location, date, time, current
enrollment, and maximum enrollment allowed) is held in a Excel spreadsheet.
5.
A separate Excel spreadsheet contains some information (name, address, phone,
email, credit card info) about previous seminar attendees.
6.
The seminar manager requested a new daily report showing the current status of
enrollment for all seminars.
21
ERD Activity: Seminar Registration System
Recall that we refined the initial set of objectives given to us by the customer
by identifying the underlying primary business needs, and by constructing and
refining a Level 0 DFD for the proposed system, which is reproduced on the
next slide.
In this activity, using the Level 0 DFD and the understanding that we have
gained about the proposed system, to create an Entity Relationship Diagram
(ERD) that models the major entities and their relationships (including
cardinalities).
Once you complete the ERD, identify (or create) primary keys for each entity,
and decide what foreign keys will be required to connect the various entities.
Finally, identify additional attributes that would be important to store for each
entity.
Level 0 DFD
Attendee Info*
seminar_cancellation
Email Sys
seminar_cancelled
Class Admin
registration_decline
confirmation_of_cancellation
request_for_transcript
catalog_search_req
Seminar
Attendee
registration_req_w_cc
registration_req_w_corp_pmt
payment_info
Proposed
System
credit
action
Corporate
Financial System
cancellation
confirmation_of_seat
confirmation_of_cc_pmt
transcript
Seminar Mgr
certificate
search_results
Seminar Info*
* Customer will convert current data