CIS4365: Database Applications
Fall, 2017

What is a Database??

Databases have become THE most important Information System package for Corporations. Without them, most companies would have a hard time functioning. MOST (and that truly means almost all) Companies could NOT exist without them."

It can also be defined as :

"A database is a large, logical, integrated collection of data and metadata"

??? What is Metadata ???

Metadata is data about data. It describes how and when and by whom a particular set of data was collected, and how the data is formatted. A good example of metadata is a data dictionary. As we will see later, a data dictionary contains such information as what fields are contained in a table, and what types of data are stored in that field.

??? What is data ???

Data is a non-random collection of symbols. Unless we know how it is laid-out and what it represents, it doesn't really mean anything to us. We might store the data:

Smith, Mary 34 92 123 MIS 778 INFOSYS


But that really doesn't tell us anything about about Mary.

??? What is Information ???

Information is something that increases our knowledge. For example, the statement:

Mary is an 'A' Student

Tells us something about Mary (She is an 'A' Student).

??? How else can we characterize databases ???

It is a way of modeling the 'real-world' . It refers to entities (something we wish to keep data on), entity attributes (specific data about an entity)  and the relationships between entities. For example, The university, keeps a lot of information about you.  All of this data is stored in a database.

Consider the following statement:

"You are an entity with attributes which vary. Within the University,  different areas have different interests in you (i.e., the Registrar, the Bursar, etc.). Nonetheless, you are still part of the University as a whole"

 Item  Database Component  Stored As
 You  Entity  Record
 Your Height, Weight, etc,  Attribute  Field
 5'2", 5'9", 6'2", etc  Attribute Value  Specific Data type
 Registrar, Bursar, etc  File/Database  Tables/Files
 University  Database  Database

Additional References:

  1. What is a Database?
  2. http://www.fukada.com/selena/tutorials/sql/toc.html
  3. http://databases.about.com/mbody.htm

Questions You Should be able to answer:
  1. Data is:

    a.  knowledge
    b.      a non-random collection of symbols
    c.  an organized collection of numerical data
    d.  a collection of entities, attributes and relationships
    e.  all of the above

    Answer: B
     
  2. Information is:

    a.      Something that increases our knowledge
    b.      a non-random collection of symbols
    c.  an organized collection of numerical data
    d.  a collection of entities, attributes and relationships
    e.  all of the above

    Answer: A
     
  3. What is the Definition of a database?

    Answer:     A large, logical, integrated collection of data and metadata
     

This page was last updated on 02/26/04.