978-0134474021 Chapter 18 Solutions Manual Part 1

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CHAPTER 18

IMPLEMENTING AN REA MODEL IN A RELATIONAL DATABASE

SUGGESTED ANSWERS TO DISCUSSION QUESTIONS

18.1 How would the process of generating a cash disbursements journal from the REA

data model presented in Figure 18-4 and Table 18-1 differ from the process for

creating a sales journal?

The steps required to create a cash disbursements journal would be simplier than the

The information typically recorded in a cash disbursements journal includes the date,

Thus, the information necessary to produce a cash disbursements journal can be found by

18.2 Why take the time to develop separate REA diagrams for each business cycle if the

ultimate objective is to combine them into one integrated enterprise-wide data

model? Why not just focus on the integrated model from the start?

One way to think about it is divide and conquer. Modeling each business cycle

individually makes it easier to be sure to identify all the relevant resources, events, and

It is also easier to assign cardinalities to relationships in REA diagrams for a single

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Ch. 18: Implementing an REA Model in a Relational Database

18.3 Building separate tables for every relationship (1:1, 1:N, and M:N) does not violate

any of the rules for building a well-structured database. Why then do you think that

REA data modelers recommend building separate tables only for M:N relationships

and using foreign keys to implement 1:1 and 1:N relationships?

To reduce the number of tables. It is more efficient to use foreign keys for relationships

than to build separate tables.

This also simplifies queries because fewer tables are needed to retrieve information.

Consider the task of generating a list of payments received from a particular customer. If

the 1:N relationship between customers and the Receive Cash event is implemented using

18.4 Assume that there exists a 1:1 relationship between the Receive Inventory and

Disburse Cash events. How does the manner in which the relationship between the

two events is implemented (i.e., in which table a foreign key is placed) affect the

process used to record payments made to suppliers?

If the primary key of the Receive Inventory table was included as a foreign key in the

Disburse Cash table, then recording payments to suppliers would involve adding a new

18.5 Refer to Figure 18-4 and Table 18-1. How would you determine the amount of cash

that Fred’s Train Shop has at any point in time?

To calculate the amount of cash that Fred’s Train Shop has at a particular point in time,

you would need to query three tables: Cash, Disburse Cash, and Receive Cash. The Cash

table would include the cash on hand at the beginning of the current fiscal year. The

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Accounting Information Systems

18.6 Why does Figure 18-4 show only one cash disbursement entity if Fred’s Train Shop

uses a general operating checking account for purchases of inventory, supplies, and

operating expenses such as rent but also uses a separate checking account for

payroll?

REA models do not represent actual physical accounts but types of accounts. Thus, even

though Fred’s Train Shop uses two checking accounts, the REA displays a single entity

for cash. This entity contains information about all of Fred’s individual checking

Then, when there is a cash disbursement it would be linked to the specific record or row

in the cash table that represented which of the two checking accounts for Fred’s Train

18.7 Examine Figure 18-4 and Table 18-1. Why do the Inventory, Customers, and

Suppliers tables all have an attribute that contains data about the balance at the

beginning of the current fiscal period?

The reason that all three entities contain an attribute that stores the beginning balance is

that the related event tables typically contain information for only the current year. Thus,

the beginning balance attribute represents information about prior years’ events.

This information about beginning balances is needed in order to calculate current

balances at any point in time. For example, the Inventory table would show the quantity

The Customer and Supplier tables contain information about the beginning balances of

Accounts Receivable and Accounts Payable for specific customers and suppliers,

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Ch. 18: Implementing an REA Model in a Relational Database

SUGGESTED ANSWERS TO THE PROBLEMS

18.1 Refer to Problems 17.1 and 17.2 for information about the revenue and expenditure

cycle activities for Joe’s ice-cream shop in order to draw an integrated REA

diagram of both cycles.

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Accounting Information Systems

18.2 Develop a set of tables to implement the integrated REA diagram you developed in

Problem 18.1 for Joe’s ice-cream shop in a relational database. Specify a primary

key for each table, and suggest at least one other attribute that should be included in

each table.

Table Primary key Other attributes foreign keys in italics

Employees Employee# Name, date hired, salary, position

Vendors Vendor# Name, address, beginning account balance

Inventory-Inventor

Item#

Sales-Inventory Invoice#, Item# Quantity, UnitPrice

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Ch. 18: Implementing an REA Model in a Relational Database

16.3 Refer to Problems 17.3 and 17.4 for information about Sue’s

Gallery’s revenue and expenditure cycle activities in order to draw

an integrated REA diagram of both cycles.

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Accounting Information Systems

16.4 Develop a set of tables to implement the integrated REA

diagram you developed in Problem 18.3 for Sue’s Gallery in a

relational database. Specify a primary key for each table, and

suggest at least one other attribute that should be included in

each table.

Table Primary key Other attributes foreign keys in italics

Vendor Vendor# Name, address, phone, contact, account balance

GLAccount#

Customer Customer# Name, address, beginning balance

Note: The cost and sales price are attributes of the inventory table because each unique

item is only purchased once and sold once.

16.5 The following tables and attributes exist in a relational database:

Table Attributes

Vendor Vendor#, name, street address, city, state

Inventory Receipts – Cash

Disbursed

Check#, receiving report#, amount applied to invoice

Draw an REA diagram for this database. State any additional assumptions you need

to make about cardinalities.

The solution appears on the following page. Students should be able to suggest adding

the entities connected by dotted lines, even though they are not listed in the problem. Key

assumptions about cardinalities include the following:

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Ch. 18: Implementing an REA Model in a Relational Database

Vendors do not make partial shipments. If you assume otherwise, then the cardinality

The inventory in question is not unique one-of-a-kind items. If it were, the maximum

The existence of an Inventory Receipts – Cash Disbursed table with an attribute in it

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Accounting Information Systems

18.6 Refer to Problems 17.8 and 17.9 for information about the revenue and expenditure

cycles for the Computer Warehouse and use that information to draw an integrated

REA diagram for both cycles.

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Ch. 18: Implementing an REA Model in a Relational Database

18.7 Develop a set of tables to implement the integrated REA diagram you developed in

Problem 17.6 for the Computer Warehouse in a relational database. Specify a

primary key for each table, and suggest at least one other attribute that should be

included in each table.

Table Primary key Other attributes (foreign keys in italics)

Vendor Vendor# Name, address, phone, contact

Employees Employee# Name, date hired, salary, date of birth,

position

Receive

Inventory-Inventor

Receiving Report#,

Item#

Quantity, condition

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Accounting Information Systems

18.8 Explain how to calculate the total amount of accounts payable:

Total Accounts Payable can be calculated in five steps, as follows:

Step 1: Normally, only orders actually received are considered purchases for purposes of

Step 2: Query the Order Inventory – Inventory table to determine the total amount

Step 3: Retrieve the total beginning balance of Accounts Payable by querying the

Step 4: Query the Disburse Cash table to calculate the total amount paid to suppliers this

Step 5: Total Accounts Payable = Answer to Query 2 + Answer to Query 3 – Answer to

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