Introduction to Database Management

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Outline Database characteristics DBMS features Architectures Organizational roles

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Initial Vocabulary Data: raw facts about things and events Information: transformed data that has

value for decision making Essential to organize data for retrieval and

maintenance

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Database Characteristics Persistent : stable storage

Shared : multiple users and uses

Interrelated : data stored as entities and relationships

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University Database

University Database

Registration

GradeRecording

FacultyAssignment

CourseScheduling

Entities: students, faculty, courses, offerings, enrollmentsRelationships: faculty teach offerings, students enroll in offerings, offerings made of courses, ...

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Water Utility Database

Billing

MeterReading

PaymentProcessing

Service Start/Stop

Entities :customers, meters, bills,payments, meter readingsRelationships :bills sent to customers,customers make payments,customers use meters, ...

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Database Management System (DBMS) Collection of components that support

data acquisition, dissemination, storage, maintenance, retrieval, and formatting

Enterprise DBMSs Desktop DBMSs Embedded DBMSs Major part of information technology

infrastructure

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Database Definition Define database structure before using a

database Tables and relationships SQL CREATE TABLE statement Graphical tools

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University Database

Relationships

Tabless

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University Database (ERD)

StdSSNStdClassStdMajorStdGPA

StudentOfferNoOffLocationOffTime

Offering

EnrGrade

Enrollment

Registers

Accepts

CourseNoCrsDescCrsUnits

Course

FacSSNFacSalaryFacRankFacHireDate

Faculty

Has

Teaches

Supervises

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Nonprocedural Access Query: request for data to answer a

question Indicate what parts of database to retrieve

not the procedural details Improve productivity and improve

accessibility SQL SELECT statement and graphical

tools

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Graphical Tool for Nonprocedural Access

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Application Development Form: formatted document for data entry

and display Report: formatted document for display Use nonprocedural access to specify data

requirements of forms and reports

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Sample Data Entry Form

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Sample Report

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Procedural Language Interface Combine procedural language with

nonprocedural access Why

Batch processing Customization and automation Performance improvement

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Transaction Processing Transaction: unit of work that should be

reliably processed Control simultaneous users Recover from failures

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Database Technology EvolutionEra Generation Orientation Major Features

1960s 1st Generation File File structures and proprietary program interfaces

1970s 2nd Generation Network Navigation

Networks and hierarchies of related records, standard program interfaces

1980s 3rd Generation Relational Non-procedural languages, optimization, transaction processing

1990s 4th Generation Object Multi-media, active, distributed processing, XML enabled

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DBMS Marketplace

Enterprise DBMS Oracle: dominates in Unix; strong in Windows SQL Server: strong in Windows DB2: strong in mainframe environment Significant open source DBMSs: MySQL,

Firebird, PostgreSQL Desktop DBMS

Access: dominates FoxPro, Paradox, Approach, FileMaker Pro

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Data Independence Software maintenance is a large part

(50%) of information system budgets Reduce impact of changes by separating

database description from applications Change database definition with minimal

effect on applications that use the database

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Three Schema Architecture

View 1 View 2 View n

ConceptualSchema

InternalSchema

ExternalLevel

ConceptualLevel

InternalLevel

External toConceptualMappings

Conceptualto InternalMappings

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Differences among Levels External

Forms Reports

Conceptual Tables

Internal Files needed to store the tables Extra files to improve performance

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Client-Server Architecture

Database

Database

a) Client, server, anddatabase on thesame computer

b) Mulitple clients and 1 serveron different computers

c) Multiple servers and databases on different computers

Client

Server

Client Server

Client Server Server

DatabaseDatabase

Client

Client

Client

Client

Client

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Organizational Roles

Indirec t Param etr ic Pow er

F unctiona l User

T echnica l Non T echnica l

D BA A na lys t/Program m er M anagem ent

Inform ation S ys tem s

Spec ia l iza tion

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Database Specialists Database administrator (DBA)

More technical DBMS specific skills

Data administrator Less technical Planning role

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Summary Databases and database technology vital

to modern organizations Database technology supports daily

operations and decision making Nonprocedural access is a crucial feature Many opportunities to work with databases