| I have an abundance of information but little first hand knowledge.
The following information is extracted from two texts which you
may want to research. The first is C.J.Date's "An Introduction
to Database Systems", Volume I, 4th edition, Addison-Wesley, 1986.
Chapter 21 discusses DATACOM/DB in detail. The second is James
Martin's "Fourth Generation Languages: Volume II Representative
4GLs", Prentice-Hall, 1986. Starting on page 185 is a discussion
of IDEAL, ADR's 4GL for DATACOM/DB. Both of these books are carried
by SOFTPRO in Burlington, MA.
Because of the rapid changes is Database products of late and the
time it takes for these authors to get their books to press you
may want to check another resource for an update.
From C.J.Date:
DATACOM/DB is a product of Applied Data Research, Inc. (ADR) for
IBM mainframes running either DOS or MVS. it may be regarded as
a typical example of an inverted list DBMS. {this is followed by
a general discussion of invested list technology, most relevant
is the fact that most relational DBMS use the inverted list model
as the underlying physical implementation. The primary difference
is that relational hides the indices and some other physical properties
from the user whereas in inverted list models these are visible
and must be manipulated by the user}.
Some other important aspects of inverted list versus relational:
1. First, the rows of an inverted list table, unlike relational,
are considered to be ordered in some physical sequence.
2. Next, an ordering may also be defined for the total database
in which, for example, all the rows of table A are considered to
precede all the rows of table B.
3. Only fields which have a search key (index) defined may be used
to locate a row. Unlike relational where all keyed and non-keyed
fields are candidates for inclusion in a Where clause.
DATACOM/DB Data Definition is done interactively via a forms interface
to the ADR dictionary (DATADICTIONARY). The data manipulation language
is anything but intuitive. The verbs strongly resemble macro names,
for example: GSETP, LOCKX, GETPS, LOCNX,...).
From James Martin: (quoted except for typos)
"The data base management system marketed by ADR is DATACOM/DB, and
its associated 4GL is IDEAL. According to the vendor, IDEAL is an
acronym for Interactive Environment for an Application's Life Cycle."
"IDEAL integrates many application-development functions within a
simple environment and supports nonprocedural functions for the
design of screens, reports, data definitions, and procedures. The
product incorporates a structured, very high level procedural language
and an integrated data base sublanguage. IDEAL supports structured
control constructs, transparent file support, screen panel management,
and arithmetic capabilities."
"IDEAL currently" [1986] "does not offer as braod a range of functions
as some older full-function 4GLs such as FOCUS and RAMIS II. Compared
to these language, IDEAL lacks a query language, decision-support
functions, financial analysis facilities, a natural English interface,
an integrated micro-to-mainframe link, and a full-function,
personal-computer version of the product. However, IDEAL is a recent
product and is likely to support a much broader range of integrated
functions in the future."
"IDEAL is designed for use by data processing professionals."
Other ADR products:
DATAQUERY DATAREPORTER DE-II (data entry facility)
ADR/D-NET ADR/DL ADR/LOOK
ADR/PC DATACOM ADR/METACOBOL ADR/DATA DESIGNER
ADR/ROSCOE ADR/DATA DICTIONARY ADR/THE LIBRARIAN
ADR/DATASECURE ADR/VOLLIE ADR/EMAIL
ADR/EMPIRE ADR/ETC ADR/VSAM TRANSPARENCY
ADR/DL1 TRANSPARENCY
"The following limitations of the current IDEAL product have also
been cited by users;
Large amounts of code. ...
Reporting Limitations...
No Symbolic Debugging...
Lack of Full Integration...
Run-Time Inefficiencies... "
(note the "..." in the preceding indicates there's more in the
paragraph)
James Martins Commentary
"IDEAL was a late entrant into the world of 4GLs. By the time it
was introducted in 1983, it was clear that much could be done to
improve on the early 4GLs. Many of the early languages were clumsy,
ill-structured, and difficult to use, cound not perform certain
types of operations, and needed exits to COBOL or other languages.
In contrast, IDEAL is an exceptionally clearly structured product.
It is easy to understand, elegant in its simplicity and easy to
use. ... IDEAL is designed for data processing professionals. although
not integrated with IDEAL, ADR has a separate query language
(DATAQUERY), a report generator (DATAREPORTER), and a data-entry
facility (DE-II). These facilities are accessible via interaces
with DATACOM/DB.
"Prototypes can be built quickly with IDEAL. An end user with suitable
training can create simple prototypes or can work with an analyst
to refine the prototypes. It is important to note, however, that
IDEAL does not eliminate the need for programming. Most nontrivial
IDEAL applications require a substantial amount of procedural code."
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Hope this is helpful in migrating the customer from DATACOM/DB to
Rdb.
<><><><> Sandy
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