Paul is a GIS professor at Vancouver Island U, has a PhD from U of British Columbia, and has taught stats and programming for 15 years.
In this lesson, learn what data are and compare different types. Understanding how to represent and organize data is a key element of using a computer.
Data are basic values or facts. Note that the term 'data' is considered plural in the scientific community, as in 'the data are collected', not 'the data is collected'; however, not everyone follows this, so sometimes you'll see data used as singular.
Every task a computer carries out works with data in some way. Without data, a computer would be pretty useless. It is, therefore, important to understand how to represent and organize data. This lesson will look at different types of data used in computer systems, how they are represented in digital form, and how they are organized in databases.
Analog vs. Digital Data
There are two general ways to represent data: analog and digital. Analog data are continuous - it is 'analogous' to the actual facts it represents. Digital data are discrete and broken up into a limited number of elements. Nature is analog, while computers are digital.
Many aspects of our natural world are continuous in nature. For example, think of the spectrum of colors. This is a continuous rainbow of an infinite number of shades. Computer systems, on the other hand, are not continuous but finite. All data is stored in binary digits, and there is a limit to how much data we can represent. For example, a color image on a computer has a limited number of colors - the number might be very large, but it is still finite.
Consider the example of color in a bit more detail. The very first monitor displays were essentially text terminals with only a single color. White or light-green text appeared on a black background. Newer monitors used more colors, enough to represent basic images, but still were quite limited. Modern displays have millions of colors and look much more natural. Still, the number of colors is finite.
Types of Data
Computer systems work with different types of digital data. In the early days of computing, data consisted primarily of text and numbers; however, in modern day computing, there are lots of different multimedia data types, such as audio, images, graphics and video. But, ultimately, all data types are stored as binary digits. For each data type, there are very specific techniques to convert between the binary language of computers and how we interpret data using our senses, such as sight and sound.
We can't talk about data without mentioning a database. A database is an organized collection of data. Instead of having all of the data in a list with a random order, a database provides a structure to organize the data. One of the most common data structures is a database table. A table consists of rows and columns. Each row is typically called a record, while each column is typically called a field.
This is an example of a simple database table of customers. Each customer has a unique identifier (Customer ID), a name, and a telephone number - these are the fields. The first row is called the header row and indicates the name of each field. Following the header row, each record is a unique customer.
While this example is very simple, you can easily imagine what else might be stored in such a database. For example, you might store the customers' mailing addresses, billing information, history of past purchases, etc. For an organization with many thousands of customers, this quickly becomes a large database.
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To use a large database effectively, you can use a database management system. A database management system is specialized software to input, store, retrieve and manage all the data.
Data vs. Information
Now, let's consider the difference between data and information. They are both related, but making a distinction is useful, especially when working with computer systems. Data are basic values. They can be unstructured and lack context. For example, a list of text entries and a list of numbers would be considered data.
Information helps us answer questions. In order to do this, data has to be organized or processed in a useful manner. For example, the list of text numbers could be a list of the names of customers, and the list of numbers could be their telephone numbers. Knowing what the data represent - and which name belongs to which number - gives structure and context to the data, resulting in information.
The distinction between data and information is useful, but it does depend on the perspective of the user. For example, if you want to make sales calls, the list of customer names and phone numbers is not very informative - you want to know what they've bought in the past, what type of business they're in, how large their organization is, etc. So, from this perspective, the list of names and phone numbers are just data, and you need additional data to get at the information you're really interested in.
Let's review. Data are basic values or facts. Computers use many different types of data stored in digital format, such as text, numbers and multimedia. Data are organized in database tables, and database management systems are used to work with large databases. A proper understanding of data allows you to organize it into useful information.
Data Terms & Definitions
Analog versus Digital Data
basic values or facts; the term 'data' is considered plural in the scientific community
data are continuous - it is 'analogous' to the actual facts it represents
data are discrete and broken up into a limited number of elements
an organized collection of data
Database management system
specialized software to input, store, retrieve and manage all the data
When this lesson concludes, you will know how to:
Contrast analog and digital data
Describe a database and recognize the purpose of a database management system
Discuss the difference between data and information
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