Data Resource Management

Lecture 9

Database Structures

1. Hierarchical Structure

2. Network Structure

3. Relational Structure

4. Multidimensional Structure

5. Object-Oriented Structure

3 – Relational Structure

All data elements within the database are viewed as being stored in the form of simple tables

Represents data as two-dimensional tables called relations

Relates data across tables based on common data element

Relation is described as a table

Relational Structure

Table Relation Row Tuple Column Attribute

Three basic operations in Relational Database Select

Creates subset of rows that meet specific criteria Join

Combines relational tables to provide users with information

ProjectEnables users to create new tables containing only relevant information

Relational Database

Relational Database

Three basic operations in RDBMS

4 – Multidimensional Data Model

Multidimensional databases combine data from a multitude of data sources.

Multi-dimensional databases are especially useful in sales and marketing applications that involve time series.

Large volumes of sales and inventory data can be stored to ultimately be used for logistics and executive planning.

For example, data can be more readily segregated by sales region, product, or time period.

Multidimensional Data Model

The data cube is a conceptual representation of database which can be implemented in a variety of ways, including top-down, bottom-up, and arrays.

5 – Object-Oriented Databases

Object-oriented DBMS: Stores data and procedures as objects that can be retrieved and shared automatically

Object-relational DBMS: Provides capabilities of both object-oriented and relational DBMS

Object-Oriented Databases

Can accommodate more complex data types including graphics, pictures, voice and text

Encapsulation – data values and operations that can be performed on them are stored as a unit

Inheritance – automatically creating new objects by replicating some or all of the characteristics of one or more existing objects

Object-Relational DBMS

An object-relational database (ORD) or object-relational database management system (ORDBMS) is a database management system (DBMS) similar to a relational database, but with an object-oriented database model: objects, classes and inheritance

In addition, it supports extension of the data model with custom data-types and methods.

Evaluation of Database Structures

Hierarchical data structure is best for structured, routine types of transaction processing.

Network data structure is best when many-to-many relationships are needed.

Relational data structure is best when ad hoc reporting is required.

Types of Databases

Conceptual categories of databases1. Operational Databases

2. Distributed Databases

3. External Databases

4. Hypermedia Databases

1 – Operational Databases

Store detailed data needed to support the business processes and operations of a company

Also called Subject Area Databases (SADB), Transaction Databases, Production Databases

2 – Distributed Databases

Many organizations replicate and distribute copies or parts of databases to network servers at variety of sites

Distributed databases can reside on network servers on world wide web, corporate intranets or extranets, or on any other company network

Distributed databases may be copies of operational or any other type of databases.

Replication and distribution is done to improve database performance at end user worksites

Distributed Databases

Centralized DatabaseUsed by single central processor or multiple

processors in client/server network

Distributed DatabaseStored in more than one physical location

Partitioned database Duplicated database

Distributed Databases

3 – External Databases

Contain a wealth of information available from commercial online services and from many sources on the World Wide Web

4 – Hypermedia Databases

Hypermedia database consists of hyperlinked pages of multimedia (text, graphic, and images, video clips etc.)

Data WarehouseDefinition: Large database that stores data that has been

extracted from the various operational, external, and other databases of an organization

Central source of data that has been Cleaned Transformed Cataloged

Data Warehouse Stored data is used for

Data Mining Online Analytical Processing Market Research Decision Support

Data Warehouses are subdivided into: Data Marts

Databases that hold subsets of data from a data warehouse that focus on specific aspects of a company, such as a department or a business process

Data Warehouse

Supports reporting and query tools

Stores current and historical data

Consolidates data for management analysis and decision making

Improved and easy accessibility to information

Ability to model and remodel the data

Data Warehouse & Data Marts

Data Warehouse & Data Marts

Retrieving Information from Data Warehouse

Database Management Software (DBMS)Definition: Software that controls the creation,

maintenance, and use of databases

Use of DBMS

Database Maintenance

Updating a database continually to reflect new business transactions and other events

Updating a database to correct data and ensure accuracy of the data

Database Interrogation

Definition: Capability of a DBMS to report information from

the database in response to end users’ requests

Query Language – allows easy, immediate access to ad hoc data requests

Report Generator - allows quick, easy specification of a report format for information users have requested

Database Query vs. Report

Management Information Systems, 7th Edition, James A. O’Brien, George M. Marakas. Chapter 5

References

Data Mining

Definition: Analyzing the data in a data warehouse to reveal

hidden patterns and trends in historical business activity

Data Mining Uses

Perform “market-basket analysis” to identify new product bundles.

Find root causes to quality or manufacturing problems.

Prevent customer attrition and acquire new customers.

Cross-sell to existing customers. Profile customers with more accuracy.

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