Business computing

Databases (cont’d)

7 january 2004

Databases

• At first they are much less intuitive than Word or Excel

• Word offers electronic sheets equivalent to pieces of paper

• Excel offers the electronic equivalent of grid paper to make computations. It is still somewhat intuitive

• Access is not intuitive at first

Database

• A tool to – Store– Treat– Display

• structured information

• Bodies of structured information are everywhere in business

Information in business

• Most of the information we work with in a professional environment is STRUCTURED

• And therefore is stored and treated and displayed with databases

Difficulties

• 1. « Where is the data ? »– The storing and the display of the data are TWO

DIFFERENT functions– Data are stored into Tables– They are displayed with Forms

• 2. « What is it useful for ? »– At first Databases seem

• Bizarre and confusing• Kind of obvious• Useless

The simplest structured information

• One-table databases : the electronic equivalent of a shoebox with cardboard cards

• Most information in a business context is better stored into multi-table databases

bdcomptoir.mdb

• It is a sales activity database of a wholesaler of food products

• It has more than 2000 basic records (the table « détails commandes »)

• The information is stored into eight tables

Information system

• A large database is called an information system

• Escem’s information system (information on students, teachers, employees…) is called ALIENOR

Examples of business databases

• An information system containing information about clients, prospects, products, and linked to production is called a Customer Relationship Management system (CRM)

• Most modern firms use CRM (for instance Dell computer)

Examples of business databases

• An accounting system usually is a database• The elementary record is « a transaction »

– Date– Description– Account debited– Account credited– The monetary amount– Some comments– And plenty more information (for instance a sale for

cash does not require to record who paid, but a complete sales CRM system will still record that…)

Deliveries to a plant

• Modern delivery systems to a plant require frequent small deliveries, instead of monthly large stock deliveries

• That’s to reduce stocks, and costs (and also not to hide potential problems)

• It is called Supply Chain Management (SCM)

A car assembly plant

• Two generations ago car assembly chains would the same model all along the chain

• Now in a car assembly plant one will see different models following each other on the chain

• The models correspond to actual demands from customers

• This requires a huge network and flow of information between the dealerships, the plant, and the supplyiers.

Use of databases

• Databases are a tool to– Store– Treat– Display

• information that has a repetitive structure

• The main example to understand is a shoebox holding cards, with the same pattern of information on each card (fields with the same titles)

Intuition

• The use of Word is very intuitive : an electronic sheet, on our screen, replaces a real piece of paper

• The usefulness of Excel is reasonably intuitive : cells displayed on a grid enables us to make calculations on (for instance) financial data

• The database Access is not as intuitive. At first it will seem strange, obvious, and useless.

• Yet it is the most important and powerful software of the Microsoft Office suite

Most information dealt with in business is structured

• Information about clients, and past relationships, has a steady structure and can be put into a database. It is usually called a Customer Relationship Management database (CRM)

• Accounting systems usually are databases : the basic record is a TRANSACTION (date, description, accout debited, account credited, the monetary figure, and some comments)

• Most accounting softwares in the market are customized databases

Escem Information System

• Large databases are called Information Systems (I.S.)

• There is an I.S. at Escem, storing all relevant information about students, teachers, and employees.

• It is called ALIENOR

The C.N.I.L.

• Databases are so powerful to control us, and to make money…

• …that in France there is a commission to prevent abusive use of databases in our daily life (without us knowing)

• It is called the Commission Nationale Informatique et Libertés

The simplest databases are one-table

• They are the electronic equivalent of a shoebox with cards

• Most business databases are more complex. They use several tables. They are called multi-table databases.

An address book

• If some of the information is repeated from person to person, it should be stored only once in another table.

• For instance there should be a separate table for cities, which only one record per city

• Then there should be a link between people’s records and the city’s records

Storing and Displaying

• In a database, data are stored in tables

• They are displayed with the help of forms

• At first we have the reflex « where are the data ? »

• The data is stored in tables. It is not usual to look at the data « in the guts of the tables »

Databases

• A very powerful business software– To store– To treat– To display

• structured information (information made of items with a repetitive pattern)

• Structured information is met all the time in business

Examples of structured information

• A client database. For each client we shall record– Name– Address– Past orders– Preferences– Turnover– Etc.– Last visit…

• Such a database will help us have an efficient sales activity

• Modern sales activities are called Customer Relationship Management (CRM)

• Dell computer uses CRM to have a very efficient sales activity (short delays, offers calibrated to the client, etc.)

Examples of structured information

• The accounting system of a firm.• The basic record is « a transaction ». The fields

are– The date– The description– The account debited– The account credited– Some comments

• All the rest of the work is done by the database• Most accounting softwares are actually

databases customized for accounting purposes.

Examples of structured information

• The Just in Time delivery system of a plant.• Modern plants receive their purchases several times per

day. They keep very little stocks• A big database (called a Management Information

System) stores, treats and delivers information from the plant to the suppliers

• The field is called Supply Chain Management (SCM)

• A new customer entering a car dealer to buy a new car will spurr a long chain of information to the plant and the suppliers. The car will be manufactured for the specific client. (Very little stock…)

The problem of stocks

• The old way to satisfy customers was to have a large choice ready at hand

• It costs a large stock, some of which will not be sold

• … Higher prices• Modern techniques with Management

Information Systems make possible the satisfaction of clients with little stocks and little delays.

• If I order a Dell computer from Dell’s site, it will be manufactured for me in the next few days !

Escem M.I.S.

• Escem keeps most of the information on students and teachers, and other employees into a database called ALIENOR

• Databases are so powerful that in France there is a commission in charge of preventing the abusive usage of databases : the CNIL (commission nationale informatique et liberté)

Simple databases

• Simple databases are one-table databases

• But all databases used in real life (in business) are multi-table databases

• The tables are « linked »

Problem with one-table databases

• A field in which we repeat many times the same information (for instance City) in an electronic address book is a source of mistakes

• Databases architects recommand to create a separate table for the cities and to link the « city_table » to the field « city » in the main « person_table »

Architecture of a database

• When we want to organize into a database a large quantity of structured information, we first of all have an architecture job

• Choose the tables and the links we shall use

• There is no single good answer

Primary key of a table

• In any table it is always good to have one field where each record has a different information

• That will help the database in sorting operations

• Usually Access offers to add a special field called « primary key », but we can force another field to be a primary key IF it has different information for each record

A good architecture

Facts about databases

• It is always disturbing the greenhorn : « where is the data ? »

• We have to distinguish Storing, and Displaying (and even Treating)

• Databases at first appears Bizarre, Obvious, and Useless

• Yet they are a very powerful business tool• Everybody uses them• It takes practice to discover this

Storing and Displaying

• Databases distinguish strongly between storing and displaying

• Data are stored into tables (artfully architectured)

• Data are displayed the way we like (in forms, and in reports, and other things)

• It is not usual to go into the « guts of the tables » to look at the data

Databases in business

• Databases are tools to– Store– Treat– Edit

• structured information

• Many types of sets of information we work with in business are structured

Database

• A tool less intuitive than word processors, or even spreadsheets

• Yet it is even more powerful• The more we work with databases the more we

realize that it a very powerful and useful tool

• It is normal at first to find databases somewhat strange, obvious and useless

• Yet soon we change our mind

The simplest structure : a one table database

• One table

• Made of many records

• Records are equivalent of cards (in a cookbook recipe collection)

• On each record we have several fields (the same on each record)

• In each field we have specific information (specific of the record)

Examples of structured data in business

• Client database

• Sales departments of firms make a heavy use of databases

• Prospect database

Examples of structured data in business (2)

• Accouting : an accounting system can be (and should be) organized into a database : the basic record is « a transaction »– A date– A description– A debited account– A credited account– Various comments

• Accounting softwares usually constructed on databases (sometimes even only on Excel, with its database capabilities)

Examples of structured data in business (3)

• Human ressources departments usually use databases to manage the firm’s workforce

• Large and complex databases are called « Management Information Systems » or just « Information systems »

• Escem uses an information system for its students and teachers, named Alienor

Examples of structured data in business (4)

• Databases are used in manufacturing, to pilot plants

• They are used in airlines reservation and management : Sabre is a huge Management Information System

• They are used everywhere

Usual databases are more complex than a one-table database

• Databases are usuallly built with several tables

• They are then called multitable databases

• The tables are « linked »

• Advantages :– Avoid repeated information– Make for an easier architecture