Database Modernization

Database modernization entails the migration of hierarchical data structures (IMS/DB (DL/I)), data and logic to a relational database system (e.g. SQL DB2, Oracle, etc).
Converting an organization's database from hierarchical brings with it many advantages including cost, stability and efficiency. Ensuring applications continue to function is one of the key questions which needs to addressed.

Other advantages include:

  • Use of SQL - A standard, humanized, universal language with an abundance of developers
  • Greater selection of OEM database products
  • Easier integration of modern day technology and applications
  • Greater advances in security
  • Limitless communication interfaces across a multitude of databases and systems
  • Performance - Easier storage, retrieval, deletion, security, and integrity of data within a database

Traditionally, databases were built based upon hierarchical models consisting of segments. Each segment had a "Parent" and "Children". Where the parents can have many children, each child can have only one parent there is only one route to and from that child. IMS/DB is based upon the hierarchical database.

Following is an excerpt of an employee hierarchical database, where each employee is a segment, containing attribute fields such as department, qualification level and personal data. On the other hand, Relational Databases (e.g. Oracle, SQL and DB2) have flat structures, enabling each attribute to have a multitude of relationships. In the same example, the Employee master table, is complimented by tables listing the attributes. Each employee, department and qualification have their own dataset and the tables are linked by through common ids (hence relational).
Many organizations are embarking on project to move to relational databases - the challenge is to preserve the considerable investment made to date.

Why change?

  • Efficiency: The interaction between batch, online and other data exchange activities and queries, occurs is much more efficient and therefore improves the overall performance of the system in question.
  • Cost: Proprietary language licenses and maintenance are typically expensive. Further development of such applications is typically difficult, restricted and likewise expensive.
  • Resource availability: It is increasingly difficult to find qualified staff with the ability to administer, maintain or indeed further develop hierarchical databases.
  • Availability: The market place has over the years of course reacted to the emergence of relational databases, and now there is little or no availability of mainstream hierarchical database systems and hence support

The migration of IMS/DB to a relational environment requires three main steps.

  1. The recreation the data structures, logic and queries of the IMS/DB within the relational table environment.
  2. Population of the new database with the data from the IMS/DB
  3. Configuration of the interpreter layer ensuring a seamless integration of unchanged applications with the new database environment


  • Key component in overall IT database modernization strategy
  • Immediate and significant reduction license and maintenance costs
  • 30 years experience right here


  • Support application enhancement
  • Short payback periods
  • Addresses the issue of scarcity of resources

If you want to know more about HTWC's Database Modernization and Hierarchical to Relational application go to H2R - IMS/DB to Relational Database page, or This e-mail address is being protected from spambots. You need JavaScript enabled to view it. with any further questions.