Database Reference
In-Depth Information
DBMS Evaluation and Selection
When a company decides to purchase a new DBMS, the DBA leads the DBMS evaluation and selection effort. To
evaluate the DBMS candidates objectively, the DBA usually prepares a checklist similar to the one shown in
Figure 8-8. (This checklist applies specifically to a relational system because most DBMSs are, at least in part,
relational. If the DBA had not already selected a data model, such as the relational model, the DBA would have
added a
category to the list.) The DBA evaluates each prospective purchase of a DBMS
against the categories shown in the figure. An explanation of each category follows Figure 8-8.
“
Choice of Data Model
”
1.
Data Deinition
a.
Data types
(1) Numeric
264
(2) Character
(3) Date
(4) Logical (T/F)
(5) Memo
(6) Currency
(7) Binary object (pictures, drawings, sounds, and so on)
(8) Link to an Internet, Web, or other address
(9) User-deined data types
(10) Other
b.
Support for nulls
c.
Support for primary keys
d.
Support for foreign keys
e.
Unique indexes
f.
Views
2.
Data Restructuring
a.
Possible restructuring
(1) Add new tables
(2) Delete existing tables
(3) Add new columns
(4) Change the layout of existing columns
(5) Delete columns
(6) Add new indexes
(7) Delete existing indexes
b.
Ease of restructuring
3.
Nonprocedural Languages
a.
Nonprocedural languages supported
(1) SQL
(2) QBE
(3) Natural language
(4) Language unique to the DBMS. Award points on the
basis of ease of use as well as the types of operations
(joining, sorting, grouping, calculating various statistics,
and so on) that are available in the language. You can
use SQL as a standard against which you can judge the
language.
b.
Optimization done by one of the following:
(1) User (in formulating the query)
(2) DBMS (through built-in optimizer)
(3) No optimization possible; system does only sequential
searches.
4.
Procedural Languages
a.
Procedural languages supported
(1) Language unique to the DBMS. Award points on the basis
of the quality of this language both in terms of the types
of statements and control structures available and the database
manipulation statements included in the language.
(2) Java
(3) C or C++
(4) GUI language such as Visual Basic
(5) COBOL
(6) Other
b.
Can a nonprocedural language be used in conjunction with
the procedural language (for example, could SQL be
embedded in a COBOL program)?
5.
Data Dictionary
a.
Type of entries
(1) Tables
(2) Columns
(3) Indexes
(4) Relationships
(5) Users
(6) Programs
(7) Other
b.
Integration of data dictionary with other components of
the system
FIGURE 8-8
DBMS evaluation checklist
(continued)
