cis 465 - information and databases 1 information and databases

CIS 465 - Information and Databases 1

Informationand Databases


Data Modeling: Documenting Information Architecture

• Information Architecture - a conceptualization of how the information requirements are met by the system.

• From the user’s viewpoint:– What information is in the system?– How is the information organized?– How can users obtain whatever information

they need?


Entity Relationship Diagrams

• What kinds of things does the system collect information about? – entities

• What is the relationship between these entities?– Relationship or association among entities

• What specific information does it collect about each of those things?– attributes


Entity-relationship diagram for part of a university registration system


Types of relationships in entity-relationship


Possible Attributes for the Entity Types

DEPARTMENT•Department identifier•College•Department head•Scheduling coordinator

COURSE•Course number•Department •Required of department major (y/n)•Course description

SECTION•Section identification number•Semester•Year•Classroom•Start time•End time•Days of week for class meetings

PROFESSOR•Employee identification number•Name•Address•Birthdate•Office telephone•Social Security number

STUDENT•Student identification number•Name•Address•Birthdate•Telephone•Gender•Ethic group•Social Security number

OFFICE•Office number•Building•Telephone extension


Use of E-R Diagrams

• E-R Diagrams are actually used for the non-technical purpose of identifying the types of things within the system’s scope and the relationships among these types of things.


Types of Data in Today’s Information systems

• Pre-defined Data - numerical or text items whose meaning are specified explicitly.

• Text - letters, numbers, and other characters where the meaning is not pre-defined.

• Images - data in the form of pictures• Audio - data in the form of sound• Video - combination of pictures and sound

displayed over time.• Future types: taste and smell?


Images produced by information systems


Review of Some Database Concepts

• What is a database?• Database management system• Logical vs. physical views of data• files, records, fields, keys• relational databases• normalization• SQL• Push vs. Pull systems.• Pre-programmed vs. ad-hoc


Some new Data base Concepts

• Multi-dimensional databases:– most relational database models are optimized to support

transaction processing.

– Business professionals often wish to analyze large amounts of data frequently, e.g. along dimensions of product, time period, and store.

– There is a significant difference between transaction processing vs. analytical processing.

– Multi-dimensional databases help support data warehouses which we will discuss further later in the semester.


Multi-dimensional Databases

• Transaction Systems:– Insert an order for 300 baseballs– Update this passenger’s airline reservation.– close-out accounts payable records for this vendor.– What is the current checking account balance for this customer?

• Analytical Support Systems:– Did the sales promotion last quarter do better than the same

promotion last year?– Is the five-day moving average for this security leading or

trailing actual prices?– Which product line sells best in middle-America and how does

this correlate to demographic data.


A Multidimensional database


Geographic Information Systems

• Organizing data so that it can be accessed by pointing at a region on a map.

• Based on spatial or geographic coordinates.• Marketing and planning applications can visualize

customers• The important distinction between GIS and other

types of information systems is not in the database, but in the access method (i.e. through maps).


A geographical information system


Some Information ConceptsSome Information Concepts

• Data: Unorganized facts and figures. (raw material)• Information: Data that has been processed into a form that

is meaningful to the recipient and is of real of perceived value in current or prospective actions or decisions.

• Information:– adds to a representation– corrects or confirms previous information– has “surprise” value in that it tells us something we did

not know, or could not predict.– What is a “finished product” to one, may be “raw

materials” to someone else.


Definitions: Information vs. Knowledge

• Knowledge: a combination of instincts, ideas, rules, and procedures that guide actions and decisions.

• Helping to provide the best available knowledge to decision-making is another role of information systems


Relationship Between Data, Information, and Knowledge

• The difference between data and information is easy to remember.

• It is often cited as the reason why systems that collect large amounts of information fail to meet management’s information needs.

• There are many methods of converting data into information for decision making.

• Managers take action based on information about a current situation plus their accumulated knowledge. Actions taken feed the process of accumulating more knowledge (experience).

• Example: How do medical students become competent physicians?


Relationship Between Data, Information, and Knowledge


Attributes of Quality Information

• Timeliness• Completeness• Conciseness• Relevance• Accuracy• Precision• Appropriateness of Form


Special Characteristics of Information

• Usefulness - depends on combination of quality,accessibility,and presentation.

• One person’s information may be another person’s noise.

• Soft data may be as important as hard data.• Ownership of information may be hard to maintain.• More information is not always better (information

overload).• Politics can often hide or distort information.


Review: Information Needs - Operational vs. Strategic

• Time frame - historical vs. predictive for the future

• Currency - highly current vs. can be quite old

• Expectation - anticipated vs. surprise

• Source - largely internal vs. largely external

• Scope - well-defined, narrow vs. very wide

• Level of aggregation - detail vs. summary

• Frequency - real-time vs. periodic

• Organization - highly structured vs. loosely structured

• Precision - highly precise vs. not overly precise


Question?

• What special attributes or characteristics of information have affected you as an individual or as part of a group?


Determinants of Information Usefulness and Related Roles of Information Systems

INFORMATION QUALITY

•ACCURACY

•PRECISION

•COMPLETENESS

•AGE

•TIMELINESS

•SOURCE


Determinants of Information Usefulness and Related Roles of Information Systems

INFORMATION ACCESSIBILITY

•AVAILABILITY

•ADMISSIBILITY

INFORMATION PRESENTATION

•LEVEL OF SUMMARIZATION

•FORMAT

INFORMATION SECURITY

•ACCESS RESTRICTION

•ENCRYPTION


Do managers expect the truth?

cis 465 - information and databases 1 information and databases

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