Database Management System Vs File Management System

A Database Management System (DMS) is a combination of computer software, hardware, and information designed to electronically manipulate data via computer processing. Two types of database management systems are DBMS’s and FMS’s. In simple terms, a File Management System (FMS) is a Database Management System that allows access to single files or tables at a time. FMS’s accommodate flat files that have no relation to other files. The FMS was the predecessor for the Database Management System (DBMS), which allows access to multiple files or tables at a time (see Figure 1 below)

comparison.jpg

File Management Systems

Advantages Disadvantages

Simpler to use

Typically does not support multi-user access

Less expensive·

Limited to smaller databases

Fits the needs of many small businesses and home users

Limited functionality (i.e. no support for complicated transactions, recovery, etc.)

Popular FMS’s are packaged along with the operating systems of personal computers (i.e. Microsoft Cardfile and Microsoft Works)

Decentralization of data

Good for database solutions for hand held devices such as Palm Pilot

Redundancy and Integrity issues

Typically, File Management Systems provide the following advantages and disadvantages: 

The goals of a File Management System can be summarized as follows (Calleri, 2001):

  • Data Management.  An FMS should provide data management services to the application.
  • Generality with respect to storage devices. The FMS data abstractions and access methods should remain unchanged irrespective of the devices involved in data storage.
  • Validity. An FMS should guarantee that at any given moment the stored data reflect the operations performed on them.
  • Protection. Illegal or potentially dangerous operations on the data should be controlled by the FMS.
  • Concurrency. In multiprogramming systems, concurrent access to the data should be allowed with minimal differences.
  • Performance. Compromise data access speed and data transfer rate with functionality.

From the point of view of an end user (or application) an FMS typically provides the following functionalities (Calleri, 2001): 

  • File creation, modification and deletion.
  • Ownership of files and access control on the basis of ownership permissions.
  • Facilities to structure data within files (predefined record formats, etc).
  • Facilities for maintaining data redundancies against technical failure (back-ups, disk mirroring, etc.).
  • Logical identification and structuring of the data, via file names and hierarchical directory structures.

Database Management Systems

Database Management Systems provide the following advantages and disadvantages: 

Advantages

Disadvantages

Greater flexibility

Difficult to learn

Good for larger databases

Packaged separately from the operating system (i.e. Oracle, Microsoft Access, Lotus/IBM Approach, Borland Paradox, Claris FileMaker Pro)

Greater processing power

Slower processing speeds

Fits the needs of many medium to large-sized organizations

Requires skilled administrators

Storage for all relevant data

Expensive

Provides user views relevant to tasks performed

 

Ensures data integrity by managing transactions (ACID test = atomicity, consistency, isolation, durability)  

 

Supports simultaneous access 

 

Enforces design criteria in relation to data format and structure 

 

Provides backup and recovery controls

 

Advanced security

 

The goals of a Database Management System can be summarized as follows (Connelly, Begg, and Strachan, 1999, pps. 54 – 60): 

  • Data storage, retrieval, and update (while hiding the internal physical implementation details)
  • A user-accessible catalog
  • Transaction support
  • Concurrency control services (multi-user update functionality)
  • Recovery services (damaged database must be returned to a consistent state)
  • Authorization services (security)
  • Support for data communication Integrity services (i.e. constraints)
  • Services to promote data independence
  • Utility services (i.e. importing, monitoring, performance, record deletion, etc.)

The components to facilitate the goals of a DBMS may include the following:

  • Query processor
  • Data Manipulation Language preprocessor
  • Database manager (software components to include authorization control, command processor, integrity checker, query optimizer, transaction manager, scheduler, recovery manager, and buffer manager)
  • Data Definition Language compiler
  • File manager
  • Catalog manager

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