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CASE tools (e.g., reverse-engineering, reengineering, and code-generating
tools) during the conversion process.
The second approach is to redesign and rewrite the access of data for the
existing nonrelational programs. The SQL statements are developed to
replace the record-at-a-time I/O code. To identify such I/O code, an analyst
must isolate data access logic from the rest of the program logic into which
the SQL statements will be placed. Because data access for some nonrela-
tional applications has similar logic, programs can be written to automati-
cally convert data access for such applications. Finally, some old programs
may have to be completely rewritten from scratch. A comprehensive
approach can be used to redesign and rewrite such nonrelational programs.
STRATEGIC ISSUES
Several strategic issues must be resolved for successful conversion to a
relational environment. The following sections describe these issues.
First, the organization's vision
of applications development responsibilities must be defined to serve as a
basis for selecting an appropriate relational DBMS. For example, if systems
development is primarily the responsibility of an IS department, the rela-
tional DBMS must not only support complete tasks for applications devel-
opment but must perform acceptably.
Applications Development Responsibility.
If end-user computing is involved in decision support applications, rela-
tional DBMS products that are equipped with high-level visual software
components (i.e., 4GL components) should be considered. These4GL com-
ponents can also be used to convert such user-developed applications as
simple reports and online information inquiry. Choosing the appropriate
relational DBMS is not easy. Many DBMS products that are claimed to be
relational may not really meet relational criteria and should therefore not
be used.
IS management should follow appli-
cations development standards to select the proper CASE tools and expert
system. As discussed in a previous section, CASE tools and expert systems,
which facilitate the migration of nonrelational systems to relational sys-
tems, perform highly automated reverse engineering and reengineering
functions. To be in a more competitive position, organizations should use
CASE products supported by industry standards.
Applications Development Standards.
Systems development management must
develop relational-specific policies, procedures, methodologies, stan-
dards, and guidelines to support the new functions introduced by the rela-
tional structure. For example, techniques for the program design and con-
struction phase should be updated so that developers may take advantage
Policies and Guidelines.
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