Database management systems vs. file systems?

Database management systems vs. file systems

• DBMS - A computerized record-keeping system
• File System - A collection of individual files accessed by applications programs.

Common limitations of some file system based DBs

• Separated and Isolated Data - Makes coordinating, assimilating and representing data difficult
• Data Duplication - Wastes space and can lead to data integrity (inconsistency) problems
• Application Program Dependencies - Changes to a single file can require changes to numerous application programs
• Incompatible Files

Advantages of a DBMS

• Data Consistency and Integrity - by controlling access and minimizing data duplication
• Application program independence - by storing data in a uniform fashion
• Data Sharing - by controlling access to data items, many users can access data concurrently
• Checkpointing and Recovery
• Security and Privacy
• Multiple views of data
• Expandability, Flexibility, Scalability
• Reduced application development times once the system is in place
• Standards enforcement
• However …..
  • Commercial DBMS often have high initial cost
  • Many DBMSs have high overhead - require powerful computers
  • DBMS are not special purpose software programs
  • Performance depends on the application

When is a DBMS not necessarily appropriate?

• Database is small with a simple structure
• Applications are simple, special purpose and relatively static.
• Concurrent, multi-user access to data is not required.
• Need a quick prototype to demonstrate feasibility
• Need an easy way to see the data without having to write a program
• Customers don’t want to install a DBMS and want to get online quickly