Software Tools - · PDF file 2006-03-04 · SE352b 3-Mar-06 (c) Hamada Ghenniwa, ECE, UWO 3 Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 5 Classification of DBMSs (Cont.) Based on

SE352b 3-Mar-06

(c) Hamada Ghenniwa, ECE, UWO 1

Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 1

SE352b Software Engineering SE352b Software Engineering Design ToolsDesign Tools

W6: W6: Database TechnologyDatabase Technology

Operational DatabaseOperational Database

Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 2

Software ToolsSoftware Tools

Source Procedure A

Source Procedure B

Source Procedure C

Systems Programming Tools

Programming Language Tools

Database System

SE352b 3-Mar-06

(c) Hamada Ghenniwa, ECE, UWO 2

Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 3

DB Related IssuesDB Related Issues

Data Models

Schemas

Schema Architecture

DBMS Languages

DBMS Component Modules

Architecture of DBMS

Quality of Design in Relational DB

SQL in general context

Query Processing

Interacting with DBs

Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 4

Classification of Classification of DBMSsDBMSs

Based on the data model used:

Traditional: Relational, Network, Hierarchical

Emerging: Object-oriented, Object-relational

Based on the number of users support

single-user (typically used with micro-computers)

multi-user (most DBMSs).

SE352b 3-Mar-06

(c) Hamada Ghenniwa, ECE, UWO 3

Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 5

Classification of Classification of DBMSsDBMSs(Cont(Cont.).)

Based on architecture centralized

consists of a single DBMS managing a single DB

distributed consists of a single DBMS (called distributed DBMS, or DDBMS) that manages several DB that might be located at different computing systems

DBMS

DB

Centralized DBS

DDBMS

DB DB

Distributed DBS

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Classification of Classification of DBMSsDBMSs(Cont(Cont.).)

A multi-database system (MDBS) supports operations on multiple DBSs,

each consists of separate DBMS or DDBMS

MDBMS

DB DB

DBMS DDBMS

Multi-DBS

DB

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Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 7

33--Level SchemaLevel Schema

Internal/Local

External

Conceptual

MDBS: 5MDBS: 5--Level SchemaLevel Schema

To support the main characteristics of MDBS, a 5-level schema architecture is required

an extended version of the 3-level schema

1. External schema

2. Federated schema

an integration of multiple export schemas

3. Export schema

a subset of the component schema that is available to the FDBS

4. Component schema

the conceptual schema of a component

5. Local schema

Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 8

DBMS

DB

Centralized DBS

MDBMS

DB DB

DBMS DDBMS

DB

MDBS: 5MDBS: 5--Level SchemaLevel Schema

DBDB--Component 1Component 1 DBDB--Component 2Component 2

MDBMS

DB DB

DBMS DDBMS

DB

33--Level SchemaLevel Schema

Internal/Local

External

Conceptual

55--Level SchemaLevel Schema

ExternalExternal External External

Federated

Export

Component1

Local

Federated Federated

Export

Component2

Local

Export

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Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 9

ThreeThree--Schema ArchitectureSchema Architecture(Cont.)(Cont.)

DATABASE

End User End User

External LevelExternal Level External Schema

VIEW External Schema

VIEW External Schema

VIEW External Schema

VIEW

Conceptual LevelConceptual Level Conceptual SchemaConceptual Schema

Internal LevelInternal Level Internal SchemaInternal Schema

Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 10

Views Views Example…Example…

Section Id

YearSemesterGradeCourse Number

Student TranscriptStudent NameTRANSCRIPT

Database

Data generated on the fly Using subject areas entities Data generated on the fly Using subject areas entities

Brown

Smith

13599FallACS3380

10299SpringBCS3320

9298FallACS1310

8598FallAMATH2410

11299FallBMATH2410

11999FallCCS1310

Database Definition

(MetaMeta--DataData)

DepartmentCreditCourse NumberCourse NameCourse NameCOURSE

InstructorYearYearSemesterSemesterCourse NumberSection IdentifierSection IdentifierSECTION

MajorClassStudent NumberNameNameSTUDENT

SE352b 3-Mar-06

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Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 11

DB Related IssuesDB Related Issues

Data Models

Schemas

Schema Architecture

DBMS Languages

DBMS Component Modules

Architecture of DBMS

Business Data Types

Quality of Design in Relational DB

SQL in general context

Query Processing

Interacting with DBs

Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 12

Business Data TypesBusiness Data Types

Operational Data

Informational Data Database System

Operational Database

Tools

Informational Database

Tools

SE352b 3-Mar-06

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Operational DataOperational Data The data used to run the day-to-day business

Typically stored in a relational database

possibly, in legacy hierarchical or flat file formats as well

Some characteristics Updated often and through online transactions

Non-historical data (not more than three to six months old)

Optimized for transactional processing

Highly normalized in the relational database for efficient update, maintenance, and integrity

Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 14

Informational DataInformational Data

Or information is a representation of the data in a way makes analysis much easier

Analysis can be in the form of decision support

executive information systems

report generation

more in-depth statistical analysis

Created from the wealth of existing operational data

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RelationalRelational Database DesignDatabase Design

∗ Conceptual design ∗ ER Model is used at this stage to capture

the core business/application concepts and rules ∗ which is then translated to a relational schema

• Schema refinement • Normalization: to tune the schema for efficiency

• check relational schema for redundancies and related anomalies

Physical database design tuning • Consider typical workloads and further refine the database design

Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 16

Conceptual DesignConceptual Design

• What? • the entitiesentities and relationshipsrelationships in the enterprise

•• informationinformation about these entities and relationships should we store in the database

• the integrity constraintsintegrity constraints that hold

• Represent this information pictorially in ER diagramsER diagrams,

SE352b 3-Mar-06

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Conceptual Design Conceptual Design ER Diagrams ER Diagrams ---- the basicsthe basics

Entities real world “objects”,

e.g. Students, Courses, Routes, Climbers. Entity sets are drawn as rectangles:

Attributes things typically used as column names,

e.g. Name, Age, Height.

Relationships relationships between entities,

e.g. a student enrolls in a course, a climber climbs a route, etc. :

Feb 24, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 18

ER: ExampleER: Example

IDEF1X Notation http://www.idef.com/IDEF1X.html

Account ID

ACCOUNT

Account Type

Own

CLIENT

Client Name

Client ID Client ID

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Relational:Relational: DefinitionsDefinitions

Key a set of attributes of a relation whose values are unique within the relation

If there is more than one key, they are called Candidate KeysCandidate Keys

Prime attributePrime attribute one which is a member of any key

Nonprime attribute

one which is not prime

primary key arbitrarily designated candidate keydesignated candidate key

all other candidate keys are Secondary KeysSecondary Keys

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Client IDClient ID Primary Key Not Nullifyable

ER: ER: Identity & Functional DependencyIdentity & Functional Dependency

IDEF1X Notation

Account ID

ACCOUNT

Account Type

CLIENT

Account ID

ACCOUNT

Client Name Account Type

Client ID Own

Client ID (FK)

Own Client ID (FK) Foreign Key