Database Reference
In-Depth Information
2.8 Summary and Concluding Remarks
Here is a summary of what has been covered in this chapter:
•
A database system can be construed as having three levels of
architecture: the external, the conceptual and the internal. These
levels are seamlessly interlinked by the DBMS.
•
The external level constitutes all the external views that end users
have of the database.
•
The conceptual level relates to the logical structure of
the database.
•
The internal level relates to the physical structure of the files
making up the database.
•
The DBA is the official responsible for the planning, construction,
Implementation and administration of the database.
•
The DBMS is the software that facilitates creation and
administration of the database.
•
A database system can be construed as being comprised of a
front-end system and a back-end system. The back-end system
relates to the actual creation and administration of the database.
The front-end system relates to the creation and administration of
the user interface through which end users access the system.
•
By applying the principle of separating front-end from back-end,
we can conceive of various database architectures.
With this background, we are now ready to move ahead and learn more about the
relational database model. You will learn the foundations of the model, and why it is
so important.
2.9 Review Questions
1.
With the use of a diagram, explain the different levels of
architecture of a database system.
2.
Explain the acronyms DSL, DML, DCL, and DDL. How are
they all related?
3.
What are the primary functions of the DBA?
4.
What are the main functions of the DBMS?
5.
With the aid of an appropriate diagram, explain how the
DBMS ensures that requests from end-users are satisfactorily
addressed.
