IT 20303 – DBMS Concepts Relational Database Theory.

IT 20303 – DBMS Concepts

• Relational Database Theory

Relational Database Theory

• The Database Environment

– Evolution of Computing Technology

• Punch-Cards – 1950-60s

• Character Based VDU – 1960-70s

• GUI – 1980-90s

• Voice/Telephony – 1990-Beyond


• The Database Environment

– Evolution of Processing Environments

• Batch Processing – 1950-60s

• Online – 1970-80s

• Networked – 1980-90s

• Future ? – 2000-beyond


• Computing Technology based on Advances in:– Hardware – economics and

miniaturization• Continues to provide increasing

power at decreasing costs• Enables a broad range of powerful

servers and workstations


• Computing Technology based on Advances in:

– Software – availability & capabilities

• Off-the-Shelf applications software

• Software to support all phases of application development


• Computing Technology based on Advances in:

– Connectivity – networking & internet

• Creates demand for web-enabled applications

• Allows interaction with many systems & databases


• Database Technology Evolution

– Files – 1950-60s

– Hierarchical – 1960-70s

– Network – 1970-80s

– Relational – 1990-beyond


• Database Technology

– Relational is the dominate database technology

– Importance of business rules is widely recognized

– Importance, use, and amount of data is increasing


• Database Technology– Our understanding of the nature of

data is expanding• Scalar (traditional) data: numbers,

character strings, dates• Complex data: graphics, images,

geographic data, audio, video, documents



– Relational DBMS capabilities are being extended

• To handle larger volumes and complex data



– Trend is to provide a GUI to the database

– Accessing the database via the web


• Impact of Technology Advances

– Systems are user-oriented rather than machine-oriented

– Rate of new technology & product introduction is very fast

– People use computers, databases, & the internet to do their jobs


• Impact of Technology Advances

– Conducting business on the internet is vital to most organizations

– Still working to provide easier user access to data

– Still seeking better ways to turn data into useful information


• Database Environment – Introduction– Components:

• Data• Users• Network• Software• Hardware• Administration


• Database & the DBMS– What is a Database?

• A collection of related data• Intended for use by a known group of

users• Designed & built for a specific set of

requirements• Represents (or models) some aspect

of the real world


• Database & the DBMS

– What is a database management system (DBMS)?

• A collection of programs

• Enables users to create, maintain, & access a database


• Why use a Database & a DBMS?

– A database supports data sharing

• Many users access the same data

• Minimizes duplicated data and resulting update inconsistencies


• Why use a Database & a DBMS?– An RDBMS is a productivity tool

• Provides efficient storage and access techniques

• Provides a standard databse access language, SQL

–Many development & case tools interface to RDBMSs



– An RDBMS provides centralized control of operational data

• Restricts access to authorized users: security

• Supports recovery of data in case of failure: durability



• Provides access by multiple users at the same time: concurrency

• Supports business rules about data values, relationships: integrity


• Different Groups of Users work with Databases– Data Administration– End Users– Data Analyst– Business Systems Analyst– Systems Analyst– Programmer Analyst– DBA


• End Users are at all levels in the organization– End Users’ primary job function is not

programming• Need information to answer questions,

make decisions, etc.• Provide input for data and process

requirements• Scattered throughout the organization


• Analysts

– Business Systems Analyst

• Expertise in business operations

• Develop specifications, process models for applications


• Analysts

– Systems Analyst

• Expertise in business applications development

• Develop specifications, models, and applications


• Analysts

– Data Analyst

• Expertise in business applications, especially data usage


• Analysts– Programmer Analyst

• Expertise in programming, application development/maintenance

–Uses VB, C++, etc.• Support day-to-day operations of

the enterprise


• Database Administrator (DBA)

– Interfaces with Users

– Builds and Populates the database

– Manages disk storage, backup, & recovery

– Maintains passwords & access authorization


• Database Administrator (DBA)

– Monitors performance & responds to changing needs

– Installs new releases of the RDBMS & related products

– Keeper of the Data Dictionary


• Database Administration

– Develops high-level data architecture

– Supports current & expected business functions

– Responsible for a global view of all the enterprise’s data


• Database Administration

– Overall data architecture can have many subject databases

• One or more subject databases can have one or many DBAs

– Integral to Information Resource Management (IRM) philosophy


• Uses of a Database

– Production Database

• Used to accomplish business functions of an organization

–Online or batch applications

–Objective is reliable, timely, valid processing of data



• Database usage includes CRUD activities

–Creating, Reading, Updating, & Deleting data (CRUD)

–Sometimes referred to as online complex processing



• Required features of DBMS often include:

–Security

–Recovery

–Concurrency

–Transaction Processing


• Uses of a Database– Decision-Support Database

• Used for analysis, querying, & reporting

–Read-Only–Sometimes referred to as

OnLine Analytical Processing (OLAP)



• Required features of DBMS environment often include:

–Easy-to-Use query tools or custom applications



• Data Warehouse

–An approach to providing a database for querying and analysis



– Individual Use Database

• A DBMS & a database in the individual user’s workstation

–Single-User environment


• Uses of a Database• Initially mass-consumer-oriented

–Example: dBASE, Paradox, FoxPro, Access

• RDBMS vendors introduced personal versions:

–Personal Oracle (Free)–IBM DB2/2 – ($600/year)–Sybase SQL Anywhere – ($200)



• Required features often include ease of:

–Installing, Use

–Reporting

–Producing simple applications


• The Database Development Process

– Requirements

– Analysis/Design

– Produce

– Build/Test

– Production Maintenance


• Roles in Application & Database Development - Logical– Data

• Data Administration• Data Analyst

–Conceptual Data Models»ERDs»Created with help of the Users


• Roles in Application & Database Development - Logical– Process

• Business Systems Analyst• Systems Analyst

–Process Model»DFD, Action Diagrams, Process

Specification Diagrams


• Roles in Application & Database Development – Physical

– Data

• Database Administrator

–Database


• Roles in Application & Database Development – Physical

– Process

• Programmer Analyst

–Program Code

IT 20303 – DBMS Concepts Relational Database Theory.

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