Learning Objectives

Upon successful completion of this chapter, you will certainly be may be to:

describe the differences between data, information, and also knowledge;define the ax database and also identify the procedures to developing one;describe the duty of a database management system;describe the attributes of a data warehouse; anddefine data mining and also describe its duty in an organization.

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Please note, over there is an updated version of this book available at https://opentextbook.site. If you space not compelled to usage this edition because that a course, you might want to check it out.

Introduction

You have currently been introduced to the very first two contents of details systems: hardware and also software. However, those two contents by themselves carry out not make a computer system useful. Imagine if friend turned ~ above a computer, began the native processor, yet could not conserve a document. Imagine if you opened up a music player however there to be no music to play. Imagine opening a web browser but there to be no web pages. Without data, hardware and software room not very useful! Data is the 3rd component of an info system.

Data, Information, and Knowledge

Data room the raw bits and pieces of info with no context. If ns told you, “15, 23, 14, 85,” you would not have learned anything. But I would have given you data.

Data can be quantitative or qualitative. Quantitative data is numeric, the an outcome of a measurement, count, or some other mathematical calculation. Qualitative data is descriptive. “Ruby Red,” the shade of a 2013 Ford Focus, is an instance of qualitative data. A number deserve to be qualitative too: if ns tell you my favourite number is 5, the is qualitative data because it is descriptive, no the an outcome of a measure or mathematical calculation.

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By itself, data is no that useful. To it is in useful, it needs to be offered context. Return to the instance above, if i told you that “15, 23, 14, and also 85″ are the number of student that had actually registered for upcoming classes, that would be information. By adding the context – that the numbers stand for the count of college student registering for details classes – I have actually converted data right into information.

Once we have actually put our data right into context, aggregated and analyzed it, we deserve to use the to make decisions for our organization. We can say the this intake of information produces knowledge. This knowledge deserve to be used to make decisions, collection policies, and also even spark innovation.

The last step increase the info ladder is the action from knowledge (knowing a lot about a topic) to wisdom. We can say that someone has actually wisdom when they can combine their knowledge and also experience to create a deeper expertise of a topic. It regularly takes many years to build wisdom on a certain topic, and also requires patience.

Examples the Data

Almost all software programs need data to do anything useful. Because that example, if friend are editing a document in a word processor such as Microsoft Word, the record you are working top top is the data. The word-processing software deserve to manipulate the data: produce a new document, duplicate a document, or change a document. Some other instances of data are: an MP3 music file, a video clip file, a spreadsheet, a web page, and also an e-book. In some cases, such similar to an e-book, you may only have the capacity to read the data.

Databases

The goal of plenty of information systems is to change data into details in order come generate understanding that have the right to be provided for decision making. In order to perform this, the mechanism must have the ability to take data, placed the data into context, and administer tools for aggregation and analysis. A database is draft for just such a purpose.

A database is an arranged collection of related information. It is an organized collection, because in a database, every data is described and also associated with other data. All info in a database must be related together well; separate databases must be developed to manage unrelated information. Because that example, a database that includes information about students have to not likewise hold information around company share prices. Databases are not always digital – a submit cabinet, for instance, could be considered a form of database. Because that the purposes of this text, we will only consider digital databases.

Relational Databases

Databases can be organized in many different ways, and thus take plenty of forms. The most popular type of database this particular day is the relational database. Popular examples of relational databases are Microsoft Access, MySQL, and Oracle. A relational database is one in which data is organized right into one or more tables. Each table has a set of fields, which define the nature the the data stored in the table. A record is one instance of a collection of fields in a table. To visualize this, think of the documents as the rows of the table and also the areas as the columns of the table. In the example below, we have actually a table of student information, v each heat representing a student and also each tower representing one piece of information around the student.

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Rows and also columns in a table

In a relational database, all the tables are associated by one or much more fields, so the it is possible to affix all the tables in the database v the field(s) they have in common. For each table, among the fields is determined as a main key. This crucial is the unique identifier for each record in the table. To help you understand these state further, let’s walk v the process of creating a database.

Designing a Database

Suppose a college wants to develop an information system come track participation in student clubs. ~ interviewing number of people, the style team learns that the score of implementing the system is to give far better insight into just how the college funds clubs. This will certainly be achieved by tracking how numerous members each club has and also how active the clubs are. From this, the team decides the the system must save track of the clubs, your members, and also their events. Using this information, the style team determines the the following tables should be created:

Clubs: this will track the society name, the club president, and also a short description of the club.Students: student name, e-mail, and year of birth.Memberships: this table will certainly correlate students v clubs, permitting us come have any kind of given student join multiple clubs.Events: this table will certainly track once the clubs meet and also how plenty of students confirmed up.

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Now the the style team has figured out which tables to create, they require to define the certain information that each table will certainly hold. This calls for identifying the fields that will certainly be in every table. For example, society Name would certainly be among the areas in the Clubs table. An initial Name and also Last Name would certainly be fields in the student table. Finally, because this will certainly be a relational database, every table should have actually a field in typical with at least one various other table (in various other words: lock should have a connection with each other).

In order come properly develop this relationship, a main key must be selected for each table. This an essential is a distinct identifier for each document in the table. For example, in the students table, it might be feasible to usage students’ last name together a way to uniquely identify them. However, the is much more than most likely that part students will share a last surname (like Rodriguez, Smith, or Lee), therefore a different field have to be selected. A student’s e-mail address might it is in a good choice for a major key, since e-mail addresses are unique. However, a primary crucial cannot change, for this reason this would average that if students adjusted their e-mail attend to we would have to remove them native the database and then re-insert them – no an attractive proposition. Our solution is to create a worth for each student — a user i would — that will act as a major key. Us will likewise do this because that each the the student clubs. This systems is rather common and also is the factor you have actually so numerous user IDs!