Learning Objectives

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

describe the differences between data, information, and knowledge;define the hatchet database and identify the steps to producing one;describe the duty of a database management system;describe the qualities of a data warehouse; anddefine data mining and also describe its duty in an organization.

You are watching: A(n) ________ is a request for data from a database.

Please note, over there is an updated execution of this book available at https://opentextbook.site. If you space not required to use this edition for a course, you might want to check it out.


You have already been introduced to the an initial two contents of information systems: hardware and software. However, those two materials by themselves do not do a computer system useful. Imagine if friend turned ~ above a computer, began the native processor, yet could not save a document. Imagine if you opened up a music player but there was no music come play. Imagine opened a web web browser but there to be no net pages. Without data, hardware and also software space not really useful! Data is the third component of an information system.

Data, Information, and Knowledge

Data space the raw bits and pieces of information with no context. If i told you, “15, 23, 14, 85,” you would not have actually learned anything. However I would have provided you data.

Data deserve to 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 i tell girlfriend my favorite number is 5, the is qualitative data due to the fact that it is descriptive, no the result of a measurement or mathematics calculation.

By itself, data is no that useful. To it is in useful, it needs to be offered context. Returning to the instance above, if i told you that “15, 23, 14, and 85″ are the number of student that had registered for upcoming classes, that would certainly be information. By including the context – that the numbers represent the counting of college student registering for specific classes – I have converted data into information.

Once we have put ours data right into context, aggregated and also analyzed it, we deserve to use the to do decisions for our organization. We have the right to say that this usage of details produces knowledge. This knowledge have the right to be offered to make decisions, set policies, and even spark innovation.

The final step increase the info ladder is the action from understanding (knowing a lot about a topic) to wisdom. We have the right to say that someone has wisdom when they can combine their knowledge and also experience to develop a deeper understanding of a topic. It regularly takes countless years to build wisdom top top a specific topic, and also requires patience.

Examples the Data

Almost all software programs call for data to do anything useful. For example, if you are editing and enhancing a record in a word processor such as Microsoft Word, the paper you room working top top is the data. The word-processing software deserve to manipulate the data: create a new document, duplicate a document, or modify a document. Part other examples of data are: one MP3 music file, a video file, a spreadsheet, a web page, and an e-book. In some cases, such as with an e-book, you may only have actually the capability to review the data.


The score of many information solution is to transform data into information in order come generate understanding that can be supplied for decision making. In order to execute this, the device must be able to take data, put the data right into context, and carry out tools for aggregation and analysis. A database is draft for just such a purpose.

A database is an arranged collection of connected information. The is an organized collection, because in a database, all data is described and also associated with various other data. All details in a database must be related as well; separate databases have to be produced to manage unrelated information. Because that example, a database that contains information about students should not likewise hold information around company stock prices. Databases room not always digital – a submit cabinet, for instance, can be taken into consideration a form of database. Because that the objectives of this text, we will certainly only think about digital databases.

Relational Databases

Databases have the right to be organized in numerous different ways, and thus take numerous forms. The most popular kind of database now is the relational database. Popular instances of relational databases space Microsoft Access, MySQL, and also Oracle. A relational database is one in which data is organized into one or more tables. Every table has actually a set of fields, which specify the nature the the data stored in the table. A record is one instance of a set of fields in a table. To visualize this, think the the documents as the rows the the table and the fields as the columns the the table. In the example below, we have a table of student information, v each heat representing a student and also each tower representing one piece of information around the student.

Rows and also columns in a table

In a relational database, all the tables are associated by one or more fields, so the it is feasible to connect all the tables in the database with the field(s) they have in common. Because that each table, among the fields is figured out as a major key. This an essential is the distinctive identifier because that each record in the table. To help you know these terms further, let’s walk through the process of developing a database.

Designing a Database

Suppose a college wants to produce an details system to track participation in student clubs. After interviewing several people, the style team learns that the score of implementing the mechanism is come give much better insight into how the college funds clubs. This will certainly be completed by tracking how countless members each club has and how energetic the clubs are. Indigenous this, the team decides the the mechanism must keep track the the clubs, your members, and also their events. Utilizing this information, the architecture team determines the the following tables should be created:

Clubs: this will certainly track the club name, the club president, and also a brief description of the club.Students: student name, e-mail, and also year the birth.Memberships: this table will correlate students with clubs, allowing us come have any given student join multiple clubs.Events: this table will track when the clubs meet and how numerous students verified up.

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Now the the style team has determined which tables to create, they need to specify the details information the each table will hold. This requires identifying the fields that will certainly be in each table. Because that example, club Name would be one of the fields in the Clubs table. First Name and Last Name would certainly be areas in the student table. Finally, since this will certainly be a relational database, every table should have actually a field in common with at the very least one various other table (in other words: lock should have actually a partnership with each other).

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