Merlyn works as a Database Administrator for DOW Inc. She is currently designing a database. She wantsto
break down the preliminary specifications into smaller components so that each component describes a basic
fragment of the specifications. Which of the following approaches is she using?
A.
Inside-out approach
B.
Top-down approach
C.
Mixed approach
D.
Bottom-up approach
Explanation:
In a bottom-up approach, the preliminary specifications are broken down into smaller components so that each
component describes a basic fragment of the specifications. These components are then represented by
schemas, some of which may consist of single concepts. The schemas are later obtained to be integrated
together until a final schema is obtained. Answer Cis incorrect. In a mixed approach, the designer
decomposes the requirements into a number of components, as in the bottom-up approach, but not to the
extent where all the concepts are separated. At thesame time, a skeleton schema is defined containingthe
main concepts of the application. This skeleton schema gives a unified view of the whole design and helps the
integration of schemas developed separately. Then the designer examines separately these main concepts
and can proceed with gradual refinements following the top-down approach or extending a portion with
concepts that are not yet represented following thebottom-up approach. Answer A is incorrect. Inside-out
approach can be regarded as a particular type of bottom-up approach. It begins with the identificationof only a
few important concepts and, based on these, the design proceeds, spreading outward ‘radially’. First the
concepts nearest to the initial concepts are represented, and a user then moves towards those further away by
means of ‘navigation’ through the specification.
Answer B is incorrect. In a top-down approach, a schema is created through a series of successive
refinements, starting from the first schema, which is gradually expanded by using appropriate modifications
that increase the detail of the various concepts. Moving from one level to another, the schema is modified
using some basic transformations called top-down transformation primitives.
In a top-down approach, a schema is created through a series of successive
refinements, starting from the first schema, which is gradually expanded by using appropriate modifications
that increase the detail of the various concepts. Moving from one level to another, the schema is modified
using some basic transformations called top-down transformation primitives.