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ITEC 1010 Information and Organizations

Chapter 5

Organizing Data and

Information

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Data

Data A necessity for almost any enterprise to carry out its

business. Consists of raw facts, and when organizedmay be transformed into information

Database A collection of data organized to meet users needs

Database management system (DBMS) A group of programs that manipulate the database andprovide an interface between the database and the userof the database or other application programs

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DBMS Discussion (1)

A collection of programs that enables you to store, modify, and

extract information from a database. There are many different types

of DBMSs, ranging from small systems that run on personal

computers to huge systems that run on mainframes. The following

are examples of database applications: computerized library systems

automated teller machines

flight reservation systems computerized parts inventory systems

From a technical standpoint, DBMSs can differ widely. The terms

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DBMS Discussion (2)

relational, network, flat, and hierarchical all refer to the way a

DBMS organizes information internally. The internal organization can

affect how quickly and flexibly you can extract information.

Requests for information from a database are made in the form of a

query, which is a stylized question. For example, the query

SELECT ALL WHERE NAME = "SMITH" AND AGE > 35

requests all records in which the NAME field is SMITH and the AGE

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DBMS Discussion (3)

field is greater than 35. The set of rules for constructing queries is

known as a query language. Different DBMSs support different query

languages, although there is a semi-standardized query language

called SQL (structured query language). Sophisticated languages for

managing database systems are called fourth-generation languages,

or 4GLs for short.

The information from a database can be presented in a variety of

formats. Most DBMSs include a report writer program that enables

you to output data in the form of a report. Many DBMSs also include

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DBMS Discussion (4)

a graphics component that enables you to output information in the

form of graphs and charts.

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Hierarchy of Data

Schematic

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Hierarchy of data Example

DatabaseDatabase

FilesFiles

RecordsRecords

FieldsFields

Characters

(bytes)

Characters

(bytes)

Personel file

Department file

Payroll file

(Project database)

005-10-6321 Johns Francine 10-7-65

549-77-1001 Buckley Bill 2-17-79

098-40-1370 Fiske Steven 1-5-85

(Personnel file)

098-40-1370 Fiske Steven 1-5-85 598 (Record containing

SSN, last name,

first name, date of

hire)Fiske (Last name field)

1000100 (Letter F in ASCII)

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Terminology

Database A collection of integrated and related files

File A collection of related records

Record A collection of related fields

Field A group of characters

Character Basic building block of information, represented by a byte

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Data Entities, Attributes, and

Keys Entity

A generalized class of people, places, or things (objects) forwhich data are collected, stored, and maintained

E.g., Customer, Employee Attribute

A characteristic of an entity; something the entity is identified by E.g., Customer name, Employee name

Keys A field or set of fields in a record that is used to identify the

record

E.g, A field or set of fields that uniquely identifies the record

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Keys and Attributes

Key field Attributes (fields)Entities

(records)

Employee # Last name First name Hire date Dept. #

005-10-6321 Johns Francine 10-7-65 257

549-77-1001 Buckley Bill 2-17-79 650

098-40-1370 Fiske Steven 1-5-85 598

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The Traditional Approach

The traditional approach

Separate files are created and stored for each

application program

Schematic

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PayrollPayroll

programs

Reports

Data FilesApplication

programs Users

InvoicingInvoicing

programsReports

Inventory

control

Inventory

control

programs

Reports

Management

inquiries

Management

inquiries

programs

Reports

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Drawbacks

Data redundancy

Duplication of data in separate files

Lack of data integrity The degree to which the data in any one file is accurate

Program-data dependence

A situation in which program and data organized for

one application are incompatible with programs and

data organized differently for another application

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Database Approach

The database approach

A pool of related data is shared by multiple

application programs Rather than having separate data files, each

application uses a collection of data that is

either joined or related in the database

Schematic

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Payroll data

Inventory

data

InvoicingData

Other

data

Database

management

system

Payroll

program

Inventory

program

Invoicing

program

Otherprograms

Reports

Reports

Reports

Reports

Database Interface Applications programs Users

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Advantages

Improved strategic use of corporate data

Reduced data redundancy

Improved data integrity

Easier modification and updating

Data and program independence

Better access to data and information

Standardization of data access

A framework for program development

Better overall protection of the data

Shared data and information resources

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Data Modeling and

Database Models (1) Planned data redundancy

A way of organizing data in which the logical

database design is altered so that certain dataentities are combined

Summary totals are carried in the data recordsrather than calculated from elemental data

Some data attributes are repeated in more thanone data entity to improve database

performance

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Data Modeling and

Database Models (2) Data model

A map or diagram of entities and their relationships

Enterprise data modeling Data modeling done at the level of the entire

organization

Entity-relationship (ER) diagrams

A data model that uses basic graphical symbols to show

the organization of and relationships between data

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Example:

Entity Relationship (ER)Diagram for a Customer

Ordering Database

Schematic

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OrderCustomer Product

1:N one-to-many

relationship

Last name Colour

Identification

number

NameFirstname

Identification

number

Attributes

Entities

1 N

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Hierarchical Database Model

Hierarchical database model

A data model in which data are organized in a

top-down, or inverted tree structure

Schematic

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Department C

Employee

1

Employee

2

Employee

3

Employee

4

Employee

5

Employee

6

Department B

Project 1

Department A

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Network Data Model

Network data model An expansion of the hierarchical database model

with an owner-member relationship in which amember may have many owners

Project 1 Project 2

Department A Department B Department C

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Relational Database Terminology

Selecting Data manipulation that eliminates rows according to

certain criteria

Projecting Data manipulation that eliminates columns in a table

Joining

Data manipulation that combines two or more tables Linked

Relating tables in a relational database together

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Linking Data Tables to Answer

an Inquiry

Schematic

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Project Number Description Dept. Number

155 Payroll 257

498 Widgets 632

226 Sales manager 598

Dept. Number Dept. Name Manager SSN

257 Accounting 421-55-99993

632 Manufacturing 765-00-3192

598 Marketing 098-40-1370

SSN Last Name First Name Hire Date Dept. Number

005-10-6321 Johns Francine 10-7-65 257

549-77-1001 Buckley Bill 2-17-79 650

098-40-1370 Fiske Steven 1-5-85 598

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Building and Modifying a

Relational DatabaseUsing MicrosoftAccess

Screen snap

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Schemas and Subschemas

Schema

A description of the entire database

Subschema

A file that contains a description of a subset of

the database and identifies which users can

perform modifications on the data items in thatsubset

Schematic

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DBMS

Schema

Subschema

B

Subschema

A

Subschema

C

User

1

User

2

User

3

User

4

User

5

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Schema Discussion

Pronouncedskee-ma, the structure of a database system, described

in a formal language supported by the database management

system (DBMS). In a relational database, the schema defines thetables, the fields in each table, and the relationships between fields

and tables.

Schemas are generally stored in a data dictionary. Although aschema is defined in text database language, the term is often used

to refer to a graphical depiction of the database structure.

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Data Definition Language

Data Definition Language (DDL)

A collection of instructions and commands used

to define and describe data and datarelationships in a specific database

Schematic

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SCHEMA DESCRIPTION

SCHEMA NAME IS XXXX

AUTHOR XXXX

DATE XXXX

FILE DESCRIPTION

FILE NAME IS XXXXASSIGN XXXX

FILE NAME IS XXXX

ASSIGN XXXX

AREA DESCRIPTION

AREA NAME IS XXXX

RECORD DESCRIPTION

RECORD NAME ISXXXXRECORD ID IS XXXX

LOCATION MODE ISXXXX

WITHIN XXX AREA FROM XXXX THRU XXXX

SET DESCRIPTION

SET NAME IS XXXX

ORDER IS XXXX

MODE IS XXXXMEMBER IS XXXX

.

.

.

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Data Dictionary

Data Dictionary

A detailed description of all data used in the

database

Schematic

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ITEC 1010Information and Organizations

NORTHWESTERN MANUFACTURING

PREPARED BY: D. BORDWELL

DATE: 04 AUGUST

APPROVED BY: J. EDWARDS DATE: 13 OCTOBER

VERSION: 3.1

PAGE: 1 OF 1

DATA ELEMENT NAME: PARTNO

DESCRIPTION: INVENTORY PART NUMER

OTHER NAMES: PTNO

VALUE RANGE: 100 TO 5000

DATA TYPE: NUMERIC

POSITIONS: 4 POSITIONS OR COLUMNS

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Data Dictionary Features

Provide a standard definition of terms and dataelements

Assist programmers in designing and writingprograms

Simplify database modification

Reduce data redundancy

Increase data reliability Faster program development

Easier modification of data and information

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Logical and Physical

Access Paths

Logical access path (LAP)

Application requires information from the

DBMS Physical access path (PAP)

DBMS accesses a storage device to retrieve

data

Schematic

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Manipulating Data

Concurrency control

A method of dealing with a situation in which two or

more people need to access the same record in a

database at the same time

Data manipulation language (DML)

The commands that are used to manipulate the data in a

database Structured query language (SQL)

A standardized data manipulation language

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Structured Query Language (SQL)

Invented at IBMs Almaden Research

Centre (San Jose, CA) in the 1970s

E.g.,

Select all (*) columns from the EMPLOYEE

table in which the JOB_CLASSIFICATION field

is equal to C2

SELECT * FROM EMPLOYEE WHERE

JOB_CLASSIFICATION = C2

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SQL Discussion (1)

Abbreviation of structured query language, and pronounced either

see-kwellor as separate letters. SQL is a standardized query

language for requesting information from a database. The original

version called SEQUEL (structured English query language) was

designed by an IBM research center in 1974 and 1975. SQL was first

introduced as a commercial database system in 1979 by Oracle

Corporation.

Historically, SQL has been the favorite query language for database

management systems running on minicomputers and mainframes.

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SQL Discussion (2)

Increasingly, however, SQL is being supported by PC database

systems because it supports distributed databases (databases that

are spread out over several computer systems). This enables

several users on a local-area network to access the same database

simultaneously.

Although there are different dialects of SQL, it is nevertheless the

closest thing to a standard query language that currently exists. In

1986, ANSI approved a rudimentary version of SQL as the official

standard, but most versions of SQL since then have included many

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SQL Discussion (3)

extensions to the ANSI standard. In 1991, ANSI updated the

standard. The new standard is known as SAG SQL.

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Database Output

Screen snap

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Popular Database Management

Systems for End Users MicrosoftAccess 98

LotusApproach 98

Inprise (formerly Borland) dBASE

DBMS Selection Criteria Database size Number of concurrent users Performance Integration Features The vendor Cost

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Distributed Databases

Distributed database

A database in which the actual data may be

spread across several smaller databasesconnected via telecommunications devices

Pretty picture

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Data Warehouse

Data warehouse

A relational database management system designed

specifically to support management decision making

Current evolution of Decision Support Systems (DSSs)

Data mart

A subset of a data warehouse for small and medium-

size businesses or departments within larger companies

Schematic

R l ti l

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Relational

databases

Hierarchical

databases

Network

databases

Flat files

Spreadsheets

Data

extraction

process

Query and

analysis

tools

Data

wharehouse

Data

cleanup

process

End user access

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Designing a Customer Data Warehouse

Sharply define your goals and objectives before

you build the warehouse

Choose the software that best fits your goals Determine who/what should be in the database

Develop a plan

Measure results

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Data Mining Applications

Data mining

The automated discovery of patterns and relationships

in a data warehouse

Data mining applications Market segmentation

Customer queries

Fraud detection

Direct marketing

Market basket analysis

Trend analysis

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On-Line Analytical

Processing (OLAP)

On-line analytic processing (OLAP) Access to multidimensional databases providing

managerially useful display techniques

Now used to store and deliver data warehouseinformation

Data warehouse and OLAP Provides top-down, query-driven analysis

Data mining Provides bottom-up, discovery-driven analysis

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Open Database

Connectivity (ODBC)

Open database connectivity (ODBC) A set of standards that ensures software written to

comply with these standards can be used with anyODBC-compliant database

Schematic

dBASE

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ACCESS

database

Lotus 1-2-3

spreadsheet

Paradox

database

ODBC Import

ODBC Link

ODBC Export

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Object-Relational Database Management

Systems (ORDBMS) Object-relational database management system (ORDBMS) A DBMS capable of manipulating audio, video, and graphical data.

Hypertext

Users can search and manipulate alphanumeric data in anunstructured way

Hypermedia

Allows businesses to search and manipulate multimedia forms ofdata

Spatial data technology Use of an object-relational database to store and access data

according to the location it describes and to permit spatial queriesand analysis

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ITEC 1010 I f i d O i i

End of Chapter 5

Chapter 6
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