All About Database Management System

I took this subject when I was second year, A.Y. 2010-2011, second semester. Anong meron sa subject na ito? From the word itself, ‘eto ang pag-aaralan. Database Management System;

database- is a collection of related data;

management- planning, organizing, leading, and controlling of 

something and;

system-  is a whole compounded of several parts or 

members. Pero, ito talaga yun…

Para mas malinaw, DBMS is a system used to create, maintain, and provide controlled access to user databases. It provides methods in adding, updating, storing and retrieving data in the database. 

Sa mga unang araw ng pag-aaral (ehemm), ang una naming tinalakay is ‘yung comparison ng traditional at  modern file processing at ang mga advantages and disadvantages nito. The advantages of database approach are: 

• Program data independence

• Palanned data redundancy

• Improved data consistency

• Increased productivity of application development

• Enforcement of standards

• Improved data quality

• Improved data accessibility and responsiveness

• Reduced program maintenance

• Improved decision support

Kaya lang, kapag may dbms, kailangan ng specialized personnel, mas mahal, kailangan ng back up copies of data at sa paggamit nito, kung di magaling mag manage eh pwedeng magkaron ng organizational conflict.

The components of the database system must also be discussed. Paano ka magsisimula kung hindi mo ito alam? 

• Computer-aided software engineering (CASE) tools

• Repository

• DBMS

• Database

• Application Programs

• User Interface

• Data and Database Administrators

• System Developers

• End users

    Database design. The database development design phases brings up the concept of data models. Knol stated that “in the implementation design phase, the conceptual data model is translated into a logical representation of the database system. The logical data model conveys the logical functioning and structure of the database  and describes 'how the data is stored' (Dan et al., 2007) (e.g. what tables are used, what constraints are applied) but is not specific to any DBMS. Logical database model is a lower-level conceptual model, which must be translated to a physical design.  Physical modelling deals with the representational aspects and the operational of the database, i.e. the internal DBMS specific operations and processes and how the DBMS interacts with the data, the database and the user. The translation from logical design to physical design assigns functions to both the machine (the DBMS) and to the user functions such as storage and security and additional aspects such as consistency (of data) and learn ability are dealt with in the physical model/schema. Practically speaking, a physical schema is the SQL coe used to build the database.” (http://knol.google.com/k/database-design-steps-how-to-develop-a-database#)

     Dito nga pag-aaralan ang ilang data models gaya ng entity relationship model which is defined as a representation of the data for an organization or for a business which is presented through ERD o entity relationship diagram. May ERD formal semantics ito that must be thoroughly understood, in order to create correct diagrams.

            Dito ko narinig ang  normalization na may iba’t ibang forms which  is the process of efficiently organizing data in a database. There are two goals of the normalization process: eliminating redundant data and ensuring data dependencies make sense. Both of these are worthy goals as they reduce the amount of space a database consumes and ensure that data is logically stored. 

     Mapapag-aralan din dito ang data administration  that has function of managing and maintaining database management systems (DBMS) software at how to manage data security na ang goal is the protection of data from accidental or intentional threats to their integrity and access. May iba’t ibang way para dito.

     Ito ang overview at naaalala ko about DBMS. Nang ma-take ko ang subject na ‘to, sa totoo lang, dun ko naramdaman ang pressure ng pagiging ComSci. :p 

adferaer

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