Essay on Database Management System ( Dbms )

1307 Words Nov 17th, 2016 6 Pages
According to (Connolly, 2003) the database is “A shared collection of logically related data, and a description of this data, designed to meet the information needs of an organization”. The Database Management System (DBMS) is software that enables users to define, create, maintain and control access to the database. The database has identified three levels of abstraction. All these three levels will have different aspects and they are as follows:

• Physical or external level- The database system can show for the users the part of the database what they need to use.
• Conceptual or Logical level- According to Connolly (2003) this level is “The community view of the database. This level describes what data is stored in the database and the relationships among the data.” This level includes the logical structure of the database. The conceptual level represents the entities, attributes and the relationships between the two of them.
• Internal or external level- According to Connolly (2003) this is “The physical representation of the database on the computer. This level describes how the data is stored in the database.” The DBMS gives the ability to share data and process resources, but as user’s needs are different therefore, the DBMS provides two different views of the data: physical and logical view.
The physical view -This is the view of the data actually stored and organized on the physical devices. (
Logical view- This is a view of the…

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