• Customer: Software developer and provider
  • Country: Denmark
  • Product Used: Ispirer Migration Service
  • Source Technology: Db2 OS/390 (z/OS)
  • Target Technology: SQL Server
  • Project Scope: 400,000 LOC
  • Project Duration: 3 months

As part of the cloud transition project, getting rid of an outdated OS/390 mainframe allowed a global HR software vendor to gain security and manageability with the latest Microsoft business solutions.


  • Gains access to the SQL Server advanced features, including excellent compression and encryption capabilities, resulting in improved data storage and retrieval functions.
  • Reduces operational expenditures and saves time and effort spent on maintaining the infrastructure used to host the OS/390 mainframe.
  • Boosts innovation and speeds time-to-market by enabling agile development and increasing system scalability.

Migrated about 400,000 lines of SQL code from Db2 OS/390 to SQL Server in 3 months


Our customer is the largest Danish company that provides HR business software and information technology consultancy. Over 1,500,000 customers rely on their software and services that simplify and digitize business processes for organizations in both private and public sectors.

The company has a global workforce of 14,000 employees in 27 countries across Europe and Latin America.


Mainframe systems are often unreliable and prone to inconsistency and data inaccuracy issues. Moreover, maintenance costs of these systems continue to rise. Since the technologies used in the current environment are outdated or no longer serve business purposes, our customer decides to switch to a cloud environment that is efficient, consistent and reliable in order to remain competitive in the market.

At the end of 2022, the customer’s management decides to abandon the OS/390 mainframe and move to Amazon Web Services. As part of that migration, the company has an opportunity to migrate from IBM Db2 OS/390 (z/OS) to Microsoft SQL Server 2019 if it is technically feasible within their time frame The system needs to go live by April 2023.


Following a thorough analysis of the migration service market, the customer's team decides Ispirer Migration Service is the most suitable solution for their migration project. Due to our demonstrated expertise in providing industry-leading database migration services with automation capabilities, we can offer the shortest delivery time, optimal cost and the highest quality of the outcome.

The main task of the Ispirer team is to transfer the Db2 OS/390 stored procedures contained in 400,000 lines of code to Microsoft SQL Server while meeting the challenging deadlines.

The project was divided into 4 stages:

At the 1st stage, the customer selected 10 stored procedures contained in 12,000 lines of code for the conversion. The Ispirer team examined the code to identify features that could be difficult to migrate.

Based on the results of the 1st stage, the following challenges were overcome by the Ispirer technical team:

  • The replacement of getDate with SYSDATETIME, TIMESTAMP -> DATETIME2(6) was automated.
  • Our experts wrote a SWF_SAVE_TRANSACTION function to replace all commits with save transactions.
  • At the request of the customer, access to some tables was implemented through functions. Since there is no equivalent of SET CURRENT PACKAGESET = SCHEMA_1; in the SQL Server database, the data from the identical tables placed in different schemas were merged with the addition of a column indicating the schema in the source database. Then access to these tables was implemented using the Func_TAB_1(@SCHEMA_1) function.
  • The team resolved an issue with DECIMAL text display. The replacement of all cases of putting a decimal into a line was automated.
  • A huge number of places where two dates were compared were automatically replaced using SWF_DB2_Timestamp with DateTime2(6) and compared as dates, not as lines.
  • All column names in all queries were carefully checked due to case sensitivity of the target environment.

At the 3rd stage, Ispirer efficiently converted the remaining Db2 OS/390 stored procedures to SQL Server based on both new and previously developed solutions.

At the final stage, after testing, the Ispirer team handed over to the customer fully functioning stored procedures in the Microsoft SQL Server environment.


Overall, it took Ispirer experts just three months to migrate IBM Db2 OS/390 stored procedures to Microsoft SQL Server. The total project scope was 400,000 lines of the converted Db2 OS/390 code.

“You have been awesome. Rarely have I had the pleasure of working with such competent and professional people. Thank you.”
The customer’s project manager

The database modernization was an important milestone in the mainframe transition to the cloud for the following reasons:

  • Through modernization, the customer has gained the benefits and capabilities of a new system that provides greater scalability, and cost effectiveness.
  • Database migration made it easy to integrate updates and new solutions in concert with other components of the overall system.
  • The modernization provided our customer with advanced security against all types of cyberattacks.