What Is Data?

Data is a collection of information stored in a database as one of several different data types. Data includes names, numbers, dollar amounts, text, graphics, decimals, figures, calculations, summarization, and just about anything else you can possibly imagine. Data can be stored in uppercase, lowercase, or mixed case. Data can be manipulated or changed; most data does not remain static for its lifetime.

Data typesare used to provide rules for data for particular columns. A data type deals with the way values are stored in a column as far as the length allocated for a column and whether values such as alphanumeric, numeric, and date and time data are allowed.

The data is the purpose of any database and must be protected. The protector of the data is normally the database administrator (DBA), although it is every database user's responsibility to ensure that measures are taken to protect data. Data security is discussed in-depth in Hour 18, "Managing Database Users," and Hour 19, "Managing Database Security."