Core concepts of accounting information systems 13 by simkin norman chapter 07

What is a Database?• Collection of organized data • Used by many different computer applications • Manipulated by database management systems DBMS... Record Structures• Data fields in ea

Prepared by Paula Funkhouser University of Nevada, Reno

Core Concepts of Accounting Information Systems, 13th Edition

Mark G Simkin ● Jacob M Rose ● Carolyn S Norman

Database Design

Chapter 7

Chapter 7: Database Design

• Uses of a modern AIS

– Systematically record data

– Provide convenient and useful formats

– Easy access to information

What is a Database?

• Collection of organized data

• Used by many different computer applications

• Manipulated by database management systems (DBMS)

Storing Data in Databases

Data must be stored and organized

Record Structures

• Data fields in each record of a database table

• Structure is usually fixed

• Example

Database Keys

• Primary Key

– Unique to each record

• Foreign Keys

– Enable referencing of one or more records

– Matches primary key of related table

Records Combined Into Report

Additional Database Issues

Administration

 Database Administrator

Documentation

 Includes a variety of descriptions

 Structures, Contents, Security Features

 Data Dictionary

 Metadata

Data Dictionary Example

Additional Database Issues

• Data Integrity

– Data Integrity controls

– Designed by database developers

• Processing Accuracy and Completeness

– Transaction controls

– Ensures accurate transaction processing

Additional Database Issues

• Concurrency

– Concurrency controls

– Prevent multi-user access at same time

• Backup and Security

– Ability to recreate data

– Prevent unauthorized access

– View controls

Steps in Developing Databases

Steps in Developing Databases

with REA

• Create Entity-Relationship Diagrams

• Identify Attributes of Entities

• Convert E-R Diagrams into Database Tables

Identify Events and Entities

Entity Examples

 Occurrence of one entity

 Associated with occurrence of one event of another entity

Cardinality Relationships

– Rectangles represent entities

– Connecting lines represent relationships

E-R Diagram Example

Relationship Tables

• Provide greater flexibility

• Need for Relationship Tables

 Linking tables with foreign keys

 Many-to-many relationships

Relationship Tables

Schematic of Database Tables

• Normalization

– Methodology ensuring attributes are stored in most

appropriate tables

– Design promotes accuracy

– Avoids redundancy of data storage

• Levels

– First normal form

– Second normal form

Unnormalized Data

First Normal Form

• In First Normal Form (1 NF) when:

– All data fields are singular

– Each attribute has one value

• Problems

– Data redundancy

– Insertion anomaly

– Deletion anomaly

First Normal Form Example

Second Normal Form

• In Second Normal Form (2 NF) when:

– It is in 1 NF

– All data items depend on primary record key

• Benefits

– More efficient design

– Eliminates data redundancy

Second Normal Form Example

Third Normal Form

• In Third Normal Form (3 NF) when:

– It is in 2 NF

– Does not contain transitive dependencies

– Data field A does not determine data field B

• Ultimate Goal

– Create database in 3 NF

Third Normal Form Example

Study Break #5

A database is in third normal form (3 NF) if it is second normal form and:

A All the data attributes in a record are well-defined

B All the data attributes in a record depend on the record key

C The data contains no transitive dependencies

D The data can be stored in two or more separate tables