Fluency with Information Technology INFO100 and CSE100 Katherine Deibel 2012-05-23Katherine Deibel, Fluency in Information Technology1

Database QueriesWho murdered the database with the candlestick in the conservatory?

Fluency with Information Technology

INFO100 and CSE100

Katherine Deibel

2012-05-23 Katherine Deibel, Fluency in Information Technology 1

Review

We have so far discussed What a database is

What database operations do Today, we will discuss

Databases as tools

How queries are used


Why use a database?

Keep records of our: Clients

Staff

Volunteers Keep a record of activities and interventions Keep sales records Develop reports Perform research Longitudinal tracking


Database Terminology

Field (columns in a table)

Smallest unit of information in a tableSometime called “attributes”

Record(rows in a table)

All related fields are collectively called a record

Table A collection of records is a data table

Database ManagementSystem (DBMS)

All the related tables, queries, data entry and edit forms, reports, macros and VBA modules that constitute a database


Fields (columns)

Records

(rows)

Anderson Thomas A 123 Marine Dr 237-1234

Benson Karen C 1300 Ohio Ave 237-8912

Casserly Rick J 12492 Rt 146 238-9011

Drummond Lynn M 1209 15th Ave N 931-4545

Table

Database Terminology

Field (columns in a table)

Smallest unit of information in a tableSometime called “attributes”

Record(rows in a table)

All related fields are collectively called a record

Table A collection of records is a data table

Database ManagementSystem (DBMS)

All the related tables, queries, data entry and edit forms, reports, macros and VBA modules that constitute a database


Fields (columns)

Records

(rows)

Anderson Thomas A 123 Marine Dr 237-1234

Benson Karen C 1300 Ohio Ave 237-8912

Casserly Rick J 12492 Rt 146 238-9011

Drummond Lynn M 1209 15th Ave N 931-4545

Table

Data | Information | Knowledge

Data (according to Information Science) Unprocessed, raw information

Information Organized, structured data that is communicated

in a coherent and meaningful manner Knowledge

Information that has been evaluated and further organized so that it can be used purposefully

Action Applying knowledge towards achieving goals


From Data to Action

We collect data Information is harvested from the data

Many companies are good at collecting data

Fewer are good at harvesting information Knowledge is elicited from the information

and put into action Database Management Systems are tools for

supporting this transformation process


Data Information Knowledge Action

Database Management Systems (DMSs)The Tools for Data to Information to Knowledge to Action


Database Management Systems

DMSs are software data tools to: Store (tables)

Organize (sort)

Add, modify or delete

Ask questions (queries)

Produce forms and reports Toolbox is a good analogy


Popular DBMs

Microsoft Access FileMaker Pro Lotus Notes Structured Query Language (SQL)

Microsoft SQL Server

Oracle

MySQL


Managing a Database

Three major distinctions Purpose of database:

Operational versus Analytical

Data representation:Flat-file versus Relational

Implementation:Desktop versus Client/Server


Selecting a DBM

Desktop databases Oriented toward single-user applications

Reside on standard personal computers Client / Server databases

Contain mechanisms to ensure the reliability and consistency of data

Offers security options on [subsets of] data

Oriented toward multi-user applications


Operational vs. Analytical

Operational databases Used to track and assist in

daily “business” activities Data typically changes

frequently over time Examples

Human resources

Mailing lists

Inventory management

Accounting systems

Point of sale systems (cash registers)

Analytical databases Tend to be more static Historical data is analyzed

for patterns or trends Often support the strategic

activities of an organization Goals may include

Predicting the future

Summarizing historical data

Prove historical assumptions


Flat-File vs. Relational

Flat-File Database All relevant data in a

single table, or series of unrelated tables

Work best for small quantities of data

Typically a person’s first databases

Relational Database Solution to data entry

redundancy problems Tables linked together

queried as if one table Linked via common

fields (columns) with exactly the same data


Flat-File Example

Weaknesses common to flat-file systems Duplicate information is repeated redundantly

Inconsistencies in how data is entered


Relational Database Example


Database Tables


Interfacing with a Relational DatabaseOur quarry is the query


Katherine Deibel, Fluency in Information Technology 19

Accessing Data in a Database

Users rarely work with the entire database Exception are the database managers

Instead, users interact through Forms: read and write data

Reports: read only All of these are based on the query

2012-05-23

Forms

Forms allow interaction with the database in a more scripted fashion

Data is read and maybe even edited


Reports

Reports are summaries generated from the database

Read-only


Katherine Deibel, Fluency in Information Technology 22

Queries

Generate a table from other tables in the database via sequences of operations Select Difference

Project Product

Union Join SQL: Structured Query Language

Standard database language

2012-05-23

Indirect SQL

SQL sequences are usually auto-generated Interfaces allow easy construction of SQL

We can view the generated SQL if we want


Query from Two Tables


Nature of the Returned Table

Some records may be editable If the data is linked to a primary key

Generally not true for collapsed data


When fields are editable

Relies on primary keys and the underlying intelligence of the database Further security settings can set edit rights

Updates can be sent out to all views Synchronization is a big issue

Editing a linked value will chance all instances


Global Update Example

Expanded database from Lab 10


Consistency Matters

A good relational database Uses IDs to connect records across tables (i.e.

relationships)

Provides specific views to meet specific users' needs

Learning these skills is beyond the scope of this course Knowing the essential ideas is part of being

fluent in databases

We will discuss some basic design on Friday


Summary

Queries, on the high-level, are the final outcome of transforming data into action

Database Management Systems provide tools for creating and manipulating queries


Project 3

You will get to explore a database by playing different roles at an interstellar travel agency Astronomical cartographer

Trip planner

Planetary information broker

End consumer


Documents

Fluency with Information Technology INFO100 and CSE100 Katherine Deibel 2012-05-23Katherine Deibel, Fluency in Information Technology1