Tutorial: Application Migration - Adding Function Emulation

Takes you through the process of adding SQL function emulation to a DB2 application, and migrating that application from DB2 to PostgreSQL using HCOPG.
The demonstrated function emulation includes:
  • Adding math functions to PostgreSQL that represent standard math functions in DB2
  • Mapping the DB2 functions to the new PostgreSQL

Prerequisites

  • If you have not already done so, review the Assumptions and Before you begin a tutorial section in the Tutorials: HCO for PostgreSQL (HCOPG) topic to ensure your environment is set up properly.
  • Before attempting this tutorial, you must first work through the steps in Tutorial: Create and Load the HCO_Test Database.

Eclipse project - FunctionEmulation

The Eclipse project we provide for this tutorial contains the FunctionEmulation project, which is a native COBOL project.

The project also contains the FunctionEmulation.cbl program, which is a COBOL SQL program that does not contain function emulation in its initial form.

The demonstration Eclipse project and its components are located in the $COBDIR/demo/sql/hcopg/functionemulation directory by default.

Sequence

To complete this tutorial, progress through these topics in the order presented here. The bottom of each topic provides Next topic and Previous topic navigational links to help you proceed in the proper sequence:

  1. Create and Map User-defined Functions
    Guides you through the steps required to create user-defined functions, and to map those functions using a text editor.
  2. Analyze the FunctionEmulation Project
    Guides you through the process of analyzing the FunctionEmulation COBOL program and project to become familiar with its use of SQL and to learn how it is compiled for HCOPG.
  3. Run the FunctionEmulation Application
    Provides step-by-step instructions to run the FunctionEmulation application using the Eclipse debugger.
Parent topic: Tutorials: Application Migration using HCO for PostgreSQL