What is Information
Defined simply, information is the stuff we want to consume (music, video, sound, writing. This definition of information overlaps with but, to me at least, is not the same as the definition of data.
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Your identity on the Net, all the data that is collected about who you are, is tied together with an identifier . It is a unique token, a string, a picture, or something else that is specific only to you. This is how we distinguish between identities, and know who is who.
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Information comes in types . For example, the main type of information on Facebook is person, but they also have events, locations, and companies. Information types have attributes associated with them. These can be optional or a requirement for that type of information. For example, Facebook requires the person type to have a name and gender. But birthday is optional. Attributes have values . For example, on Facebook the person type has an attribute called "name." In my account the name attribute has a value of "Bob Boiko." Values usually have a certain pattern or form. For example, a "date of birth" attribute must have a date pattern in the value. An information item is one complete set of values. For example, on Facebook one complete person includes values for name ("Bob Boiko"), birthday, city of birth, likes, status updates, etc. There are close to a billion "person" information items on Facebook, each with a complete set of values for the attributes of the "person" information type . But because some attributes are optional items of information can contain attributes with no value (for example not everyone fills in the birthday for their account on Facebook. But their "person" item still contains the attribute "Date of Birth." It just has no value ). We'll come back to information types, attributes , values and items later.
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The lifecycle of information is the way information is originated, used and finally retired. In the information lifecycle : Information is created . It is originated in some way either by being created from scratch or acquired from somewhere else. Information is stored in databases or other information repositories. Information is organized so that it can be found again when it is needed. Information is displayed so that people can see and use it Information is retired when it is no longer immediately useful to people
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Stage 1: creation There are 2 major ways to create an info item in a system: You can author it (type it in from scratch), or, for non-text information record it in some other way. You can acquire it from somewhere else (for example, from another database) This is what happens with UW's registration system. Food for thought: Facebook creates information by having you fill in your own profile; this means Facebook doesn't have to expend a lot of effort creating information because you do it for them. For other organizations, creating information might be their biggest expense . Think about how much time you've put in building a single "person" item on Facebook, and imagine if Facebook had to do that work for the other billion people items.
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Stage 2: storage In general, information is stored in databases . Think of them like a spreadsheet or table containing columns and rows of data. If a database is a place to store information, it must store information types, items, attributes , and values. Loosely speaking, in a database, The name of a table stores the information type . You can also say that the table as a whole is the info type The column names are the attributes. Each column of the table stores a different attribute. Each row of the table stores a sets of values (one value for each column). So, one row equals one information item .
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Stage 3: organization Accessing information by looking through all of it is inefficient and time-consuming. Organizing it allows better access . The first way we organize is by indexing (alphabetical and/or numerical lists of names). For people, the more traditional method is by last name (Boiko, Bob); a newer way that reflects how many people think about names organizes by first name ("Bob"). The second way to organize information is to link it to other pieces of information. Social graphs are just a representation of all people in your social network organized by links. A third way to organize information is by sequences . For example Facebook can put your friends in order, indicating that you should look at one friend before another. The friend list on Facebook profile pages might be arranged by who is most important, who you contact most, or something similar (not alphabetically). Google search results are arranged by what result Google thinks you should see first. The fourth choice for organization is hierarchies , or outlines. Family trees or Tables of Contents are examples of this. They organize information by levels, or , you can say, by parents and children.
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Stage 4: display What's the point of storage if what you're storing isn't used? When information is used, it's displayed . It is given back to people in some useful form. In databases, attribute values are stored. In a display , values are interleaved with other information that provides the user a context for understanding the attribute and value. For example, the display might include a user-friendly label for the value and text that explains how to interpret the value. Display also adds a look and feel , formatting that makes the information more usable and attractive. The same piece of information (value) can be used twice in a display, or not at all. However, in all cases some set of attribute values are chosen , and displayed with formatting to produce a view of the information that a user can understand.
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Stage 5: retirement When an information item is no longer useful it can be retired in several ways. An information item can stay in the display stage of the lifecycle for a long time. If the item is changed (that is, recreated), it will have to be stored again and may have to be organized again. But eventually, that information item is no longer needed. It can be deleted , and be gone entirely and forever. It can be archived and moved somewhere else for possible later reuse. Facebook has both retirement options. You can make your profile inactive (it's still in storage but it won't show up in displays), or you can delete it entirely. Food for thought: But when is something really, really deleted? Maybe never. Deletion is in the eye of the beholder. If you go to Facebook and delete your profile. What is the result? First, your information isn't immediately removed from all parts of the system. It takes a while because the information resides in multiple places. So it may be a long time before the delete propagates to all parts of Facebook Next, your information may already have been copied out of Facebook. Suppose someone has already downloaded a photo from your profile and posted it to Flickr. Now your information is in a different system, and will not be deleted. Finally, Facebook may have already given or sold your information to a third party, once again putting in a different system and out of your control. The moral of this story is: "Just because you click the delete button does not mean your information is gone.
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Summary: Information comes in types Types have attributes Attributes have values Attribute values come in varieties or patterns Information items are groups of values connected by an id or unique label. Each information item has a lifecycle . Items are: created stored organized displayed retired
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