1

Chapter 1

Introduction to Accounting Information

Systems

Chapter 5

Database

Management

Systems

Learning Objectives

• Understand techniques to model complex accounting phenomena in E-R diagram

• Develop E-R diagrams that model effective accounting database structures

• Recognize components of relational tables and keys to effective DB design

• Understand use of SQL to create relational tables during implementation

• Manipulate tables to extract data

3

Entities/Attributes

• Entity - object, event, or agent about which data are collected– Objects - Inventory, equipment, cash

– Events - Orders, sales, purchases

– Agents - Customers, employees, vendors

• Attribute - item of data that characterizes and entity or relationship

4

Attribute hierarchy for entity Client

5

Model representations for entities and attributes

6

Relationships

7

Constraints on data model relationships

EMPLOYEE WORKS_COMPLETEDWorks

EMPLOYEE WORKS_COMPLETEDWorks

a. Cardinality constraints

b. Participation constraints

1 N

(1,1) (0,N)

8

Relational Databases

• Relation - collection of data representing multiple occurrences of an object, event, or agent.

• Tuples (rows) - set of data that describe an instance of the entity represented by a relation; like a record in traditional file structure.

• Attributes (columns) - items of data that characterize an object, event, or agent; like fields in traditional file structure.

9

Mapping E-R Diagram to Database

• Create separate relational table for each entity.

• Determine primary key for each relation. Must uniquely identify any row within table.

• Determine attributes for each entity.

• Implement relationships among entities. (Primary key in one table exists as attribute in every table (entity) where relationship specified in E-R.

• Determine attributes, if any, for relationship tables.

10

Hours

Name Contact Phone_noStreet_address City State Zip_codeClient_No.

Client_No.Employee_No. Date

CLIENT

WORK_COMPLETED

Employee_No. Soc_Sec_No Supervisor_No Billing_RatePay_RateName

EMPLOYEE

TRAINING_COMPLETED

Employee_No. Date Hours Train_code

RELEASE_TIME

Employee_No. Date Hours Vacation_Sick

Schema - billing & HR database

11

Hours

Name Contact Phone_noStreet_address City State Zip_codeClient_No.

Client_No.Employee_No. Date

CLIENT

WORK_COMPLETED

Employee_No. Soc_Sec_No Supervisor_No Billing_RatePay_RateName

EMPLOYEE

TRAINING_COMPLETED

Employee_No. Date Hours Train_code

RELEASE_TIME

Employee_No. Date Hours Vacation_Sick

Referential constraints - relational schema

12

13

SQL : Relational DB Query Language

• Used to

– define database systems

– query DB for information

– generate reports from DB

– access DB from within programs

• De facto standard DB language

14

Constructing DBs using SQL

• Assign name to relation

• Assign names to attributes

• Specify data type for attributes

• Specify constraints, when appropriate, on the attributes.

15

Other SQL functions

• Update DB -– add tuple using INSERT– remove tuple using DELETE– change attribute value using UPDATE

• Query DB using SELECT/WHERE

• Generate standard reports from DB– ad hoc (as necessary)– repetitive - might generate subschema view

Learning Objectives

• Understand techniques to model complex accounting phenomena in E-R diagram

• Develop E-R diagrams that model effective accounting database structures

• Recognize components of relational tables and keys to effective DB design

• Understand use of SQL to create relational tables during implementation

• Manipulate tables to extract data