DBMS Architectures

Types



There are three schemes, by which a DBMS is formed



1. The internal scheme; in this level the stored data could be accessed from data warehouses. Let's say I want to drive a car, the first thing i have to do is to get inside, that is in simple terms what the internal scheme is about. It is the level that is closest to the computer.


2. The logical scheme; this is the level where all the work is done... data is manipulated, edited, add-ons are applied, and non usable data is deleted. In addition, it is on this level that good business sense is made out of the raw data entered, or the input that the DBMS has.


3. The external scheme; here is where the information, or data transformed to valuable business output is displayed and reaches the concerned member of the business organization. It is the closest level to the user, or users of a DBMS.(1)


(1)





Examples

• Microsoft access; it was widely used in companies for internal communication, and ease of daily tasks. Use of mass e-mails, pre-generated forms embedded in each of the companies' stores. However; newly developed products much more powerful, and faster, have taken its place. Since time is money in business, saving time using old DBMSs is a problem that is swiftly solved nowadays, thanks to the evolving market of IT. (2)
  

• Oracle; The largest market share in 2006, was for this DBMS software, skyrocketing at 47.1%(3). Companies use oracle for higher needs, it is a very powerful tool. Oracle has the RDBMS storing data logically in the form of tablespaces, it also stores data physically in the form of data files. Tablespaces are able to contain many kinds of memory segments. Most big companies rely on the effectiveness of Oracle to be time efficient, and save operation costs. (4)
  

• DB2; IBM has DB2 actively present in the market and according to "gartner.com"(3) constitutes 21.1 % of the total market share of RDBMSs. It can function on UNIX, LINUX, and WINDOWS, therefore; it makes using it very user friendly, and easily downloadable. This limits problems, and invites more companies to buy and use DB2 in their operations.(5)
  

(1) http://www.gitta.info/DBSysConcept/en/html/DBMSArchitec_learningObject1.html
(2) http://en.wikipedia.org/wiki/Microsoft_Access
(3) http://www.gartner.com/it/page.jsp?id=507466
(4) http://en.wikipedia.org/wiki/Oracle_Database#Oracle_processes
(5) http://en.wikipedia.org/wiki/IBM_DB2