Case Study
An OHIP Billing Provider
Project Overview
Migrating DG/UX, PowerHouse 4GL, COBOL and C-ISAM to SQL Server Microsoft and .NET CORE/WPF
CORE partnered with an OHIP Billing Organization (OBO) to migrate a legacy PowerHouse/COBOL system into a modern Windows Presentation Foundation (WPF) application backed by Microsoft SQL Server. While the WPF application is used to maintain the static data in the Front end, the OBO Billing backend billing application was migrated to a PowerShell/C# engine. This engine is used to perform all financial managements on claims submitted to the ministry of Health for processing. Millions of transactions are processed monthly with this new business business .
As part of this effort, all existing reports were converted into Report Definition Language (RDL) and data was reshaped to fit a new relational schema.
The Challenge
OBO’s core business application ran on PowerHouse and COBOL under DG/Unix operating system, with reporting tied to proprietary formats. Key issues included:
- Legacy Data Store: C-ISAM on DG/UX limited reporting capabilities and integration with other systems.
- Monolithic Architecture: PowerHouse screens and logic were tightly coupled with COBOL, making it hard to introduce new modules or improve performance.
- Business Continuity: OBO billing supports claims processing by 1000’s of doctors; any downtime or data loss would disrupt operations and customer trust.
- Scalability Needs: Growth in patient care and new clinic onboarding meant the system needed a more scalable relational database and a flexible, web-friendly front end.
- Stagnant Reporting Framework: Critical operational reports couldn’t be modified or expanded easily, making it hard to adapt to new reporting requirement
- Obsolete Data Storage: The legacy database structures limited performance and hindered integration with other systems, complicating downstream analytics.
- Complex Data Migration: Moving data from a mix of PowerHouse files and COBOL tables into a normalized SQL Server schema required careful rule mapping to preserve data integrity.
- Modern User Interface Needs: The old system’s text-based screens offered little in the way of a user-friendly experience, slowing daily workflo
Our Approach
Phase One: Data Migration & Foundation
- Migrated the entire DG/Unix C-ISAM and sequential files to SQL Server on Windows.
- Designed a new SQL Server schema optimized for relational queries, indexing, and maintaining historical audit trails.
- Wrote C# utilities to extract data from the old PowerHouse/COBOL structures, apply transformation rules, and bulk-insert records into the new SQL Server tables.
- Developed SQL scripts to build the target database objects—tables, stored procedures, views, and constraints—ensuring referential integrity and performance tuning.
- Created T-SQL stored procedures to transform and update data in the new relational schema, ensuring referential integrity and business-rule consistency.
- Converted the PowerHouse data dictionary into SQL Server tables to preserve metadata, field definitions, and validation logic.
Phase Two: Application Rebuild
- Reimplemented key OBO Billing modules such as web, oscar, disc upload process, month-end processing, ohip submission, payroll module, and remitance advice processses in .NET using PowerShell as theorchesstrator, C# for thebusiness logic and SSRS for the Report Format.
- Leveraged the Renaissance Architect framework for .NET to accelerate development, enforce consistent design patterns, and support future enhancements.
- Integrated WPF Data entry and inquiry forms with MS SQL Server, replacing terminal-style screens with rich-client interfaces running under a Click-Once Server.
- Built a WPF front end that replicated core functionality—patient lookups, appointment scheduling, billing entries—using a modern, form-driven interface.
- Exposed backend services via C# classes that interacted directly with SQL Server, replacing the old COBOL-based business logic with .NET methods.
- Integrated the new RDL reports into the WPF UI so users could run, filter, and export reports without leaving the application.
Testing & Quality Assurance
- Ran unit tests on each migrated module to verify business logic against legacy outputs.
- Conducted integration testing to ensure that package-tracking workflows, financial interfaces and reporting functions worked end to end.
- Performed performance tuning on SQL Server queries and .NET components to meet service-level expectations under peak load.
Knowledge Transfer & Support
- Prepared training materials and workshops on the Renaissance Architect tools for the client’s IT staff.
- Provided hands-on sessions covering schema maintenance, T-SQL updates, and .NET module enhancements.
- Established a transition plan with staged cutover steps, fall-back procedures, and post-go-live support to minimize operational risk.
Results
- Modern, User-Friendly Interface
The WPF application replaced text-based screens with intuitive data entry forms, table lookups, reducing data-entry errors and speeding up routine tasks like patient billing and scheduling. - Robust Reporting Platform
All legacy reports were now hosted in SSRS, accessible via the WPF UI. This allowed staff to generate up-to-date analytics on patient visits, revenue trends, and appointment no-shows without relying on manual exports. - Clean, Relational Data Store
The new SQL Server schema improved query performance by 60% on average for key operations (for example, filtering appointment histories). Data integrity improved because transformation rules ensured consistency during migration. - Seamless Transition
Parallel testing and incremental cutover steps meant that OBO continued scheduling and billing without interruption. After go-live, the new system required minimal troubleshooting and quickly became the standard platform for daily operations.