Data Base Management System

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DBMS

Data Base Management System an Introduction and history
editor: Cornelis Robat & Tim Vick (1) part 1 Collections
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Related Articles Introduction to software history

Everywhere in the world there are collectors. And you may take it from me; there are A LOT OF THEM. It is very human to have something you collect. There is nothing abnormal to it, rest assured. In our life, in the kitchen, or in our desk drawer at home, there is bound to be some sort of collection. So let's presume you have a collection; if not you, your partner, friend, or family member will collect something. You, he or she collects books, computers, pictures, coins, baseball caps, coasters, addresses, organs, cars, recipes, pots and pans, a collection of collectibles, or whatever collection that seems to belong together. All the money in your bank account is a collection, too. And the antique cutlery in your mom's cupboard is a collection as well. So if the 'objects' have some connection to one another, or they belong together in some way, it is a collection. Let’s assume in the years past and to come that this collection of yours has grown dramatically. Just like the picture collection of this site. It became huge! In a few years you will forget you had this special coin or recipe in your box (and another box, and another box). You will have undoubtedly some duplication in your collection. So here is a question: how do you find this little precious thing that you are not sure you have? Answer: you need some sort of organization in your collection, a registration! Registering a collection makes the registration of it a "Database". Another case: Have you ever gone to a hotel, airline, or box office at the cinema and you had a reservation but your name disappeared into nevernever land? Well it happened to me more than once. And did you start to wonder how that could be? You even ordered via the Internet! Couldn't be more sure, you thought... wrong! In 99% of all cases your name is there. Your ticket or room key will be handed over or the bus ticket is there at the counter for you. Related Resources

Everything goes well, normally. The way they keep order in this is that businesses (airlines, cinemas, hotels) also collect something: your name, address, age, telephone number, gender, name of your partner, age of your partner, are you a vegetarian, are you Singhalese, American ...

a collection of people

All this information about you is called data and is stored electronically into a document or more precisely: a file. If this file is just a few pages long, there will be no problem finding your information.

But, say a hotel collects data from a lot of people: past, present and future guests. The hotel stores preferences: smoking, non-smoking, what ever. In our simple case study our hotel is famous for its animal correctness, so why not collect the name of the guest's pet, too! Now

this will become a lot of "data" that will grow and grow and grow. And again here is the question: how do you find your way in all this information. Did the receptionist write all this data on a piece of paper?

piece of scrap paper

Disaster! Maybe the reception desk is organized and the receptionist puts all the names on stock cards? And puts them in alphabetical order?

stock card

With a lot of these cards, one or more are bound to get misplaced. Our study case: Hotel Bincker's In the last few years Hotel Bincker's has grown from a small village hostel into a medium sized business hotel in a rapidly growing small silicon village town. And the desk has no time to keep track of all

information needed to take care of its guests in a proper way. "We are a hotel not an airline!" is vaguely muttered by the manager after he lost your name again, did not cross off the room on his blackboard and booked the same room twice. But after management communicated its concern with losing clients, the manager promises to clean up his act. Some weeks later when you show up at Hotel Bincker's desk the manager will finger through his agenda which is ordered by date and he will find your reservation. This method works well for a small hotel. Guests are coming back and the hotel's business is profitable again.

Hotel Bincker''s agenda and room reservation "database"

But after some years, Hotel Bincker's has grown again. Now it is a larger hotel with some 100 rooms and the manager is still using an agenda for each floor, and then history repeats: your name is lost. The manager needs many minutes to find what room is available. It is obvious that any (paper) agenda would be too small to schedule over 100 rooms. Hotel Bincker's is losing its clientele again. This time the manager cannot rescue the situation with a simple agenda anymore. He starts complaining to his wife and kids, who start to show him their electronic agendas with all their gadgetry. Now that's an idea! Still

having his old faithful agenda and keeping track of reservations electronically. But within a day running the hotel's administration on a small PDA proves to be a useless exercise. The solution is found but something bigger is needed. The need, however, for an electronic version of a combined agenda and guest list is confirmed by the manager’s little test case. So the manager’s daughter Lisa starts browsing the Internet and finds out that a hotel reservation system would be the answer to her dad's problem. Together they start contacting companies that sell or create reservation systems. But for a small hotel like Bincker's with its specific services, no off-the-shelf system seems to be available or affordable. The step from paper agenda to a full blown computerized hotel reservation system is too big for the hotel's management and does not match with the hotel's business culture. But Lisa learned a lot while browsing the Internet and she starts explaining to her dad how a system like that would work and what such a system can do for his business. Above all, she explained how to plan such a project. Here is how Lisa started to explain to her dad how to proceed: Imagine that a hotel is nothing else than a collection of rooms and, like any collection, we need to have some form of registration. Keeping track of rooms in an orderly way can be with a list:

Rooms
Name First Gender Out

20 DEC Room 101 102 103 104 206

10:11 Smoker N N Y Y N

208 302 303

N Y N

A guest can be entered in that list when he or she arrives at the hotel:

20

Occupancy list
Gende r M M M F F M Ou t Y Y Y N N N

De c

10:1 1 Smoker N N Y Y Y Y

Name Dijkstra Romero Rubnes Voloute Xantia Zeppeli n

First Jan Paolo Jetro Mari a Citon Ger

Room 101 104 201 299 300 301

Guests and their rooms

In case we are out of vacancies we can contact our guests via our address list:

Names and Addresses
Na me Fir st Pho ne Gen der Pe t Vegeta rian Smo ker

31 Dijks tra Ja n 44 345 366 6 123 Rom ero Pa olo 452 3 350 9 101 Rub nes Jet ro 440 3 222 6 404 Volo ute Ma ria 239 6 235 0 Lisa continues: The above examples show you how a simple list of rooms and persons gets rid of the misplaced papers. Names and rooms are shown in a particular order, in this case alphabetically, so you can quickly find what you are looking for. These examples are already a small database, see? But remember a database can have any physical form: paper, on a blackboard, an electronic file, or even some tally sticks. (a very early form of some kind of registration in 1310) F N Y M Vla to N Y M Pie tro N N M Y N

tally sticks

The lists we have here can be put on a computer in a word processor document or some tabular sheet like a spreadsheet. These are called files. It is possible to combine those two in any way, already a sort of database. The difference between a database and a file is that there is something extra to it. A database must contain a method, amongst other things, to look up something. Comparable to the databases used by search engines like Google, Alta Vista, or Yahoo that we use to find companies which could sell us a reservation system. The Internet is also some kind of database. And all this information is managed by a database management system, hence DBMS. Case study: Hotel Bincker “Our biggest problem is to find rooms that are vacant and the ones that are occupied,” says Lisa. Below I have drawn an example listing for vacancies that can be called with one click of a button:

Vacancies
Name First Gender Out

01 DEC Room 102 106 101 103 202

10:11 Smoker N N Y Y N

205 302 303

N Y N

Here is part of the rooms list with guests who reserved a room for the 20th of December

20

Reservations
Gende r M M M F F M Ou t Y Y Y N N N

DE C

10:1 1 Smoker N N Y Y Y Y

Name Dijkstra Romero Rubnes Voloute Xantia Zeppeli n

First Jan Paol o Jetro Mari a Citon Ger

Room 104 108 202 292 303 301

And here is a part of the address list of persons who made reservations or have been guests at our hotel.

N a m e Di jk st ra

F i r s t J a n

Ad dre ss

N o t e s

P h o n e 3 1 4 4 3 4 5 3 6 6 6

G e n d er M

P e t

Veg etar ian

S m ok er

14 Pin ker ton lan e Del oit, 12 34 DE Del aw are US

Y e s

Y

N

A Ro m er o P a o l o Plz de 5 Ma yo 12 3 43 2523 Ro ma Ital y Ru bn es J e t r o 12 3 Pol e 23 Del ive r to mai loff ice San Re ma ro Tri nid ad Y e 1 0 1 4 4 0 3 2 2 2 6 M V l a t o N N N o 1 2 3 4 5 2 3 3 5 0 9 M P i e t r o N N

Vo lo ut e

M a r i a

12 rue de la libe rte Au xer re 12 03 94 Fra nce

N o

4 0 4 2 3 9 6 2 3 5 0

F

N

Y

When our desk manager wants to have a quick view when a room becomes available, or for that matter occupied rooms, he calls up his agenda in the form of a chart: R o o m 2 0 1 0 1 1 0 2 1 0 2 1 2 2 2 3 2 4 2 5 2 6 2 7 2 8 2 9 3 0 3 1 0 1 0 2 S U M O T U W E T H F R S A S U M O T U W E T H F R S A

3 1 0 4 1 0 5 2 0 1 2 0 2 2 0 6 2 0 7

This chart is color coded, blue is a guest, green is available, purple are reservations, yellow is a national holiday or other special day; mostly meaning prices go up. When our front desk manager wants more specifics he can open a sub window to search for a room (in all possible combinations: adjacent rooms, smoke free, etc.) Or use the more advanced form of a floor plan:

Our front desk manager will have an instant overview of all available rooms and their configuration. “That,” concludes Lisa, “is all we need.” Not a complicated system like the Hilton has, but one that offers you the information you need with one click of a button. And one where we can put in the information we have on our guests habits and likes or dislikes. “So,” asks her dad, “how would we go ahead? What do we need? A scientist? It must be a system that we can maintain by ourselves with no need for expensive consultants with little knowledge of our business.” And Lisa answers: “You know, dad; we just happen to have an assignment in our class that just covers your need.” Instantly a broad grin plays on Dad’s lips. “OK,” he says, “let's see if we can be of mutual benefit to each other.” So now you have some idea of how most automation projects start: from a certain need and/or a fear of losing business. Continue to the next chapter where I will introduce some methods and techniques used to analyze information. Footnotes & References
To remind you, these chapters do not serve as a text book on database design, but aims 1 only to give you some insight on how a DBMS is put together and what processes are

involve. In a very generic and global way. If you have any suggestions on how to make these pages any better please do not hesitate to contact the editor. 2 3

DBMS

Data Base Management System an Introduction and history
editor: Cornelis Robat & Tim Vick (1) Part 2

Introduction (continued)
Assignment:
Your goal as a software engineer is to design a user friendly, solid and above all reliable database system.

Related Articles

Introduction to software history

Related Resources

The previous examples served to give you an idea of the need to organize information. This part will show you some examples of what a software engineer uses to create a design of a

database system for our Bincker's Hotel example. The first step in your assignment is to get a picture of how this hotel business actually runs. This process is called: Analysis. There are various methods and techniques to perform such an analysis and without getting too theoretical and since this is just a quick reference text lets get our hands dirty. What stages do we need to go through to get to a fully functional system? An example is shown below.

In this chapter we constrict ourselves to the analysis part of the above diagram. There are various types of analysis:


Information Analysis; analysis of our business's processes Functional Analysis; analysis or functionality of our processes Technical Analysis; analysis of the components of our functionalities







Data analysis

What all this means is explained below.

First phase: Information Analysis

Information Analysis first of all creates an image on how a business or organization is put together and what processes are of importance. Our project primarily deals with people and how they do their jobs in keeping a hotel running and afloat. So what do they do when receiving a guest, making reservations, giving information to people, selling and serving meals, snacks and drinks and so on? In other words Bincker's hotel business has to be dissected into separate processes for us to understand how this all fits together: Receiving and registering guests Register reservations Responding to inquiries, providing information to guests Sell meals, snacks, drinks Maintenance, cleaning rooms, floors, linen... Rostering employees

Receive money for rendered services Pay salaries and bills, possibly some bribes and other expenses ...

Mind you we only deal with the large chunks here. Each chunk is called a process. And as many roads lead to Rome, there are of course several ways to put up this (primary) process lists but for now it'll do fine. Next step after identifying primary processes is to break down all primary processes into smaller processes. Until there is no part that can be called a process because everything has been broken down into basic actions. Now break down a primary process into a smaller process. Receiving and registering guests Welcome guest Ask guest his wanting (a room) Check if guest has a reservation (ask name) If no reservation check for available rooms

... Can this be broken down into even smaller processes? Check for available rooms Call up vacancy rooms list Ask guest's preferences If room available as desired claim room If OK book room Ask guest's other particulars (address, city etc.) ... Into even smaller processes? Ask guest's other particulars Enter last name, first name into form Enter address, city, country into form ...

You see the above examples show processes that are broken down into actions until there are no processes that can be identified as autonomous processes any more. In fact actions are the atoms of our processes. Atoms can also be broken down into smaller parts, but the question is if this has any added value in the cadre of our information analysis. Braking up atoms into smaller parts is part of the functional design, see introduction to program development for more details.

Below you'll see some quick and big steps through this analysis process.

At first all elementary primary business processes are identified. Shown here are the primary processes listed at random order.

Then draw a relational schematic of how all these processes are connected together.

Note: processes are not necessarily in correct order or connection, this graph just serves as an example

Important is to determine how processes are connected together. This is done by connecting the processes with lines is such a way that is is shown how one process serves as input or output for one or more other processes. Like a guest serves as input for the financial system (paying for the room) but also a input for the rooms proces. The finance process churns out money that is input for for the suppliers process (paying bills). NEW GRAPH .

Normally you continue to describe the processes.

Some elements you would like to describe


A precise description of the process itself and its role in the organization Relationships with internal and external processes The input a process needs to do its function: resources, conditions.





After you have identified all processes you might continue to determine the elements a process contains. For example the 'Guest' process contains a person. This person might have a pet. There are notes on this person and his pet, the guest’s habits and dislikes, preferences (e.g. preferred airline), trips he or she or they booked, what means of payment he/she uses, his/her business address, home address, etc, etc. So let us describe a basic guest (object).
  

A guest could be described as follows: Name Address City

  

Country Phone number email

There are many more properties one could name sample of that. A guest can be much more than just an address What makes Bincker's hotel so special is that management keeps track of its guest’s birthday, habits, likes, preferred foods, hobbies, trips he or she organized, preference of rooms, the way the rooms smells, anything that can enhance the guest’s well being and feeling at home. The hotel only 'above' five star hotels do. So here are some more properties of our 'object': guest
               

to describe a guest (called: object) below is a small

personnel take special care of their guests in a way

Birthday Married Gender Favorite dishes and drinks Dislikes Likes Smoking Pet Important habits Transport MeansOfCommunication MeansOfPayment Trips Wake-up-call Preferred airline Notes

Et cetera.

But the hotel does not only have guests, it also has relationships with suppliers and personnel and other types of relations. So let us call this list of All objects together of our relation database comprise our Relation Information System (RIS). And how will you be sure you covered everything? We will use the mind mapping technique, which is often used when analyzing objects and their relationships. Shown as an example here is part of the mind map the project (thocp.net) is using to cover all subjects at the games section.

addresses our relations database (the address list).

Important to this way of displaying relationships is that you put your focus to
the object what your business is about: your guests. In the above example that is the project's games section.

Footnotes & References

To remind you, these chapters do not serve as a text book on database design, but aims only to give you some insight on how a DBMS is put together and what processes are 1 involve. In a very generic and global way. If you have any suggestions on how to make these pages any better please do not hesitate to contact the editor. 2 3

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