A data file is a collection of logically related records. In a file management environment, each application has a specific data file related to it.

This file contains all of the data records the application requires. Over time, organizations developed numerous applications, each with an associated, application-specific data file.

Using databases eliminates many problems that arise from previous methods of storing and accessing data, such as file management systems.

Databases are arranged so that one set of software programs-the database management system-provides all users with access to all of the data.

This system minimizes the following problems:

• Data redundancy: The same data are stored in multiple locations.
• Data isolation: Applications cannot access data associated with other applications.
• Data inconsistency: Various copies of the data do not agree. In addition, database systems maximize the following:
• Data security: Because data are “put in one place” in databases, there is a risk of losing a lot of data at once. Therefore, databases have extremely high security measures in place to minimize mistakes and deter attacks.
• Data integrity: Data meet certain constraints; for example, there are no alphabetic characters in a Social Security number field.
• Data independence: Applications and data are independent of one another; that is, applications and data are not linked to each other, so all applications are able to access the same data.