When Not to Use a DBMS

In spite of the advantages of using a DBMS, there are a few situations in which a DBMS may involve unnecessary overhead costs that would not be incurred in traditional file processing. The overhead costs of using a DBMS are due to the following:

• High initial investment in hardware, software, and training
• The generality that a DBMS provides for defining and processing data
• Overhead for providing security, concurrency control, recovery, and integrity functions

Therefore, it may be more desirable to use regular files under the following circumstances:

• Simple, well-defined database applications that are not expected to change at all
• Stringent, real time requirements for some application programs that may not be met because of DBMS overhead
• Embedded systems with limited storage capacity, where a general purpose DBMS would not fit
• No multiple-user access to data

Certain industries and applications have elected not to use general purpose DBMSs. For example, many computer-aided design (CAD) tools used by mechanical and civil engineers have proprietary file and data management software that is geared for the internal manipulations of drawings and 3D objects. Similarly, communication and switching systems designed by companies like AT&T were early manifestations of database software that was made to run very fast with hierarchically organized data for quick access and routing of calls. Similarly, GIS implementations often implement their own data organization schemes for efficiently implementing functions related to processing maps, physical contours, lines, polygons, and so on. General-purpose DBMSs are inadequate for their purpose.