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Chapter 5 UNDERSTANDING AND DESIGNINGACCOUNTING DATA
Identifying and Documenting Files
Transaction files: Used to record
information about events in a business process
Identifying and Documenting Files
Transaction files: Attributes include:
Transaction date Agents associated
with transaction Description of
products/services associated with event
Identifying and Documenting Files
Master files: Store reference data Store summary data
Identifying and Documenting Files
Events and transaction files:
First, identify the events in the business process
Then, identify the need for transaction files in the AIS
Documenting Transaction Files
UML class diagram: Shows relationships
between transaction and master files
Each box represents a file
Connecting lines between files indicate file relationships
Documenting Transaction Files
UML class diagram: Can be used to
document: Tables in an AIS Relationships between
tables Attributes of tables
Documenting Transaction Files
Guidelines for identifying need for transaction tables:
1: Determine the events in the process
2: Exclude events that do not need to be recorded in the computer system
Documenting Transaction Files
Guidelines for identifying need for transaction tables:
3: Exclude query and reporting events because they involve using data that have already been recorded in the AIS
4: Exclude maintenance events
Documenting Transaction Files
Events and master tables: Typical master tables:
Products/services - master tables
Describe products/services offered
Identify costs and/or prices of products/services
Agents - master tables describe
External agents Internal agents
Documenting Transaction Files
Events and master tables:
Typical master tables Cash - master file
describes where cash is stored
General ledger master file - needed if general ledger system is
Automated and Integrated with the revenue or acquisition cycle
Documenting Transaction Files
Events and master tables:
Generally, master tables are used to store relatively permanent data about an entity
Documenting Transaction Files
Benefits of master tables:
Save data entry time Save storage space Simplify making
changes to data Simplify deleting
transaction records
Attributes and Relationships
3 important concepts Primary keys Linking attributes
(foreign keys) Relationship
cardinalities
Attributes and Relationships
Primary key: Attribute(s) that
uniquely identifies a record in a table
Attributes and Relationships
Foreign key: A field in a table that is
the primary key in some other table Used to link one
table to another Link event records to
master records Link two events that
occur in a sequence
Attributes and Relationships
Cardinality of the relationship:
(covered in the text)
One-to-one relationships (1,1) - not nearly as common as one-to-many relationships
One-to-many relationships (1,m) - common in accounting systems
Many-to-many relationships (m,m) - can be converted into two one-to-many relationships by adding a “junction table”
Attributes and Relationships
Cardinality of the relationship:
Important in designing a database
Represents how many occurrences of one type of entity are associated with another type of entity
Attributes and Relationships
Significance of concepts for database applications:
Implementing documents and reports
Attributes and Relationships
Significance of concepts for database applications:
Implementing input forms Input forms are used to
make data entry more accurate/efficient
Form designs rely on primary and foreign keys and relationships between tables
Attributes and Relationships
Significance of concepts for database applications:
Controlling AIS data – referential integrity For one-to-many
relationships Can specify if want
referential integrity enforced on relationship
Control most effective with two other controls:
Segregation of duties and
Access controls
Designing Data with a UML Class Diagram
Developing a data design using a UML class diagram:
Four basic stepsStep 1: Place the required
transaction tables (files) on the UML class diagram.
Identify events in a business process.
Decide which events will need transaction tables.
Start the UML class diagram by showing a box for each event requiring transaction tables.
Designing Data with a UML Class Diagram
Developing a data design using a UML class diagram:
Four basic stepsStep 2: Place required
master tables (files) on UML class diagram
For each event on the diagram (from Step 1), determine related goods, services, or agent entities
Determine which identified entities require master tables
Designing Data with a UML Class Diagram
Developing a data design using a UML class diagram:
Four basic stepsStep 2 (continued): Consider using master
tables to track location of cash and effect of events on account balances in the general ledger
Add required master tables to appropriate side of the UML class diagram
Designing Data with a UML Class Diagram
Developing a data design using a UML class diagram:
Four basic stepsStep 3: Determine
required relationship between tables
For each connecting lines, determine cardinality of the relationship between tables
Designing Data with a UML Class Diagram
Developing a data design using a UML class diagram:
Four basic stepsStep 3 (continued): Write cardinalities next
to line between entities If there are any many-
to-many relationships, convert them to one-to-many relationships by adding junction table
Designing Data with a UML Class Diagram
Developing a data design using a UML class diagram:
Four basic stepsStep 4: Determine required attributes by:
Assigning a primary key to each tables
Linking related tables by adding a foreign key to one of the pair in the relationship
Linkage depends on cardinality of the relationship
Designing Data with a UML Class Diagram
Additional data design implementation issues:
Suggestions One master table
instead of two One event table instead
of two Option A: Two records in two tables
Option B: One record in one table
Eliminate redundant relationships
Add relationships not involving event records
Designing Data with a UML Class Diagram
Communicating the data design:
Guidelines in preparing documentation Be consistent in
naming entities Name boxes so can
easily correlate UML diagram with preceding documentation
Help reader understand how each part of the documentation relates to other parts
Designing Data with a UML Class Diagram
Communicating the data design:
Guidelines in preparing documentation - Proper layout can also enhance readability Start each part on a
separate page Clearly label each part Write a brief explanation
of the information obtainable by reviewing diagram
Use bulleted lists to explain linkages between diagrams
Use same style throughout
Keyterms
Attributes Cardinality Database Database management
system Foreign key Primary key Referential integrity Relational database UML class diagram