Browse Prior Art Database

Transformation of an Entity-Relationship Model into a System Object Model

IP.com Disclosure Number: IPCOM000114248D
Original Publication Date: 1994-Nov-01
Included in the Prior Art Database: 2005-Mar-28
Document File: 4 page(s) / 119K

Publishing Venue

IBM

Related People

Ngo-Anh, T: AUTHOR

Abstract

Common Data Facility/MVS (CDF/MVS) is a product which is designed to store and retrieve application data based on the Entity-Attribute-Relationship (EAR) data model running in TSO using the DB2 database. CDF/MVS could be used for example as a repository database in development and manufacturing to store different kinds of data such as process data, personnel data and technical information including Binary Large Objects (BLOBs) like CAD/CAM data etc. A weak point of this product is that it only has a ISPF front end and does not provide any support for object-oriented data modelling in a Client/Server environment. This article describes the mapping of the Entity-Attribute-Relationship data model into an object oriented model using System Object Model (SOM) or DSOM (Distributed SOM) provided on the OS/2* platform.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Transformation of an Entity-Relationship Model into a System Object
Model

      Common Data Facility/MVS (CDF/MVS) is a product which is
designed to store and retrieve application data based on the
Entity-Attribute-Relationship (EAR) data model running in TSO using
the DB2 database.  CDF/MVS could be used for example as a repository
database in development and manufacturing to store different kinds of
data such as process data, personnel data and technical information
including Binary Large Objects (BLOBs) like CAD/CAM data etc.  A weak
point of this product is that it only has a ISPF front end and does
not provide any support for object-oriented data modelling in a
Client/Server environment.  This article describes the mapping of the
Entity-Attribute-Relationship data model into an object oriented
model using System Object Model (SOM) or DSOM (Distributed SOM)
provided on the OS/2* platform.  The objects can be accessed and
displayed in a Client/Server LAN based environment using Remote
Procedure Call (RPC) and the Workplace Shell of OS/2 2.x.

For the realization, the following components are required:
  1.  Data dictionary
      MVS is used as the Superserver in this environment.

          To provide the objects to the client, it is first necessary
to convert and map the entities and their attributes into objects.
This
could be solved by using a data dictionary which contains the data
extracted from the database tables.
  2.  Superserver-Server Communications

          The communication between the host mainframe and the PCs
could be set up by any available communication vehicles.  For
example,
a simple EHLLAPI communication is sufficient to transfer the
information
between the host computer and a LAN server.
  3.  Client/Server Communications via a Remote Procedure Call (RPC)
       server

          From a PC front end, the user sends the requests to the
mainframe via the RPC server.  The RPC server will directly
distribute
the data to the client if the requested data is available.  It only
routes a request to the host computer if the data does not exist on
its
system.
  4.  SOM objects in the Workplace Shell

          The data is presented to the user in form of folders and
icons, metafiles, files, or text, which are derived from a set of
classes.

    A sample application will now be described.  The application
consists of following elements:
   o  A set of products
   o  A set of specifications belonging to a product
   o  A set of persons working on the product

          The concept of classes can now be introduced.  For the
explanation, it will be assumed that CDF/MVS on the host computer
acts
as the super-server.

    On the side of the workstation there are:
  a.  a Transaction server (NTTsvr) which communicates with the MVS
     ...