Safeguard changes in advance
Use NUnit, Selenium and deterministic SHA-256 checksum tests to prove that a changed procedure returns exactly the same data as the legacy code.
Team coaching towards DevOps, CI/CD and test automation
When every new program version becomes a nail-biter, each release costs time and carries risk. I work directly in your team for a few weeks; afterwards your team ships changes itself, with automatic checks.
In grown development teams, manual deployments, missing regression tests and silos between development (.NET), database (SQL) and operations cost valuable time – every production release risks side effects. Many teams know in theory how CI/CD and automated tests should work. In day-to-day business they fail because of historically grown databases, lack of time and manual deployment rituals. No slide presentations: I do not coach from the whiteboard, I work directly in your repository.
Together in the code and the pipeline – typically 1–3 days per week over 8–12 weeks
Support directly in your team’s day-to-day work, as at NXP Semiconductors and in modernisation projects. We agree the start date in the initial call, in line with your release planning.
Format · 1–3 days per week in the team
Hands-on setup of Azure DevOps pipelines, Docker containers and reproducible database deployments on your real codebase – without bringing your day-to-day business to a halt.
Knowledge transfer · onboarding & mentoring
I work with your developers on the real code instead of showing slides. The knowledge stays in your team for good.
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1
Build the pipeline
Together we set up build and release pipelines in Azure DevOps (CI/CD) and containerise with Docker.
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Safeguard
We safeguard database procedures and .NET code with automated NUnit, Selenium and checksum tests over real data.
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3
Check in code review
We read execution plans in code review before a change goes into production.
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4
Monitor & hand over
Early-warning monitoring (PRTG) and documentation, so that your team can carry on without me.
What your team can do on its own afterwards
Check execution plans
Spot slow queries in code review, before they slow down production.
Releases at the push of a button
Ship changes independently, tested and reproducibly – without weekend nail-biting.
Why it pays off: When an internal team tries to build CI/CD and automated database tests for a grown system alongside day-to-day business, it often takes many months full of setbacks. Working together in the code, the safety net is in place within a few weeks – and the knowledge stays in your team for good.
From practice: starting point, approach, result
Two projects from corporate remediation and modernisation. More cases are on the database optimisation page.
DevOps reorganisation · around 130 procedures
International spirits group (Stock Spirits / formerly Borco): IT reorganisation, 130 procedures overhauled, Always On & backup/restore
Starting point: Transition of the IT team from an old, highly bureaucratic way of working to modern DevOps practices. In parallel, around 130 historically grown MSSQL procedures handled nightly data consolidation and error correction; their deeply nested logic blocked downstream systems.
Approach & result: As documentarian, I helped build the IT reorganisation and systematically supported the support system. Structured workflows were introduced for tickets and problem tickets (ITIL-oriented incident, problem & change management, root-cause analysis), code reviews and daily Scrum meetings. The around 130 procedures were disentangled during live operation and replaced by fast, maintainable T-SQL solutions. We also operated Always On Availability Groups (AOAG), switching server nodes alternately during updates – as in a project for the Hesse State Police (Landespolizei Hessen). Backup and recovery procedures were set up and monitored. They were also used for dataset comparisons (old vs. new when data errors were suspected) and for regular copies of live data into QA test systems (parallel tests).
“Mr Hagen has exceptionally profound technical expertise in the areas of databases, application architecture and performance optimisation. […] His work significantly improved the transparency, maintainability, stability and performance of the IT systems in use.”
— from the client’s written reference letter (translated from German)
Import wholesaler: 20-year-old desktop application with Oracle brought to the web
Starting point: A VB/WinForms application with an Oracle database, grown over more than 20 years, was to be replaced. The goal was a modern Blazor Server web application (.NET) with MS SQL Server.
Approach & result: I analysed existing components and use cases independently, planned and implemented the new architecture, and tested the new functions with NUnit and Selenium in a dedicated test environment. Business workflows were preserved, loading times became markedly shorter and licence costs were reduced.
- Oracle → MS SQL
- C# / .NET / Blazor
- Entity Framework Core
- NUnit / Selenium
At NXP Semiconductors, too, Azure DevOps pipelines, Docker and onboarding the international team were part of the work on a very large 24/7 database: see the NXP case study. The SSIS data warehouse for FDA studies at Clario is also on the database optimisation page: see the Clario case study.
Modernisation, SSIS/DWH and regulated industries
As a work package or in your team: architecture of very large databases (VLDB), interim responsibility as app owner and application modernisation (Oracle/desktop → MS SQL & C#/Blazor).
Modernising applications (.NET / Blazor)
Moving desktop and Oracle applications step by step to MS SQL Server, C#/.NET 8 and Blazor without losing business workflows. Safeguarded by automated NUnit and Selenium tests.
SSIS, data warehouse & 24/7 migration
From almost 7 years of continuous SSIS practice (Würzburg): complex ETL pipelines (SSIS with C#/.NET), data warehouses that resolve heavy normalisation, faster SSIS nightly runs and billion-row migrations in 24/7 operation.
Regulated industries, public authorities & audits
Audit-proof reporting, audit trails (FDA 21 CFR Part 11), hardening and security requirements (in line with ISO 27001 / BSI Grundschutz), Always On Availability Groups (AOAG), backup & recovery (data comparison & QA restores) and ITIL-oriented ticket/problem processes – for pharma, industry and the public sector (Hesse State Police).
How I work
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01
Measure first, then change.
No measure without a reproducible measurement before and after.
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The most effective spot first.
Preferred diagnostic strategy: index before code before hardware – a few changes with a large commercial effect.
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03
Respect what exists – and the people.
Grown systems are improved step by step; teams are taken along in their daily work instead of being lectured.
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04
Resolve island knowledge.
With COMPIDDA, clean DevOps pipelines and understandable documentation, the knowledge stays in your company for good.
Tools & search terms for procurement, HR & engineering
MS SQL Server 2019–2025 (T-SQL, query tuning, root-cause analysis, index tuning, execution plans, Always On Availability Groups / AOAG, Windows clustering, backup & recovery / QA restores, SSMS, SSIS, SSRS, data warehouse / DWH, VLDB) · COMPIDDA (static code & database analysis, audit-ready documentation) · Oracle PL/SQL · PostgreSQL · MySQL · Redis · C#/.NET 8 · ASP.NET Core · Blazor · Entity Framework Core (EF Core) · Dapper · REST/OpenAPI · NUnit · Selenium · PowerShell (helper scripts & automation) · Docker · Azure DevOps (CI/CD) · Scrum · Git · PRTG · ITIL-oriented incident, problem & change processes · ISO 27001 / BSI Grundschutz-compliant diagnostics. Available as a freelancer / independent consultant (SQL Performance Tuning Freelancer, Senior Database Architect, SSIS/DWH specialist, .NET architect, DevOps coach) remotely across the DACH region and on site when needed.
Should your team ship releases itself, without the nail-biting?
Describe in two or three sentences where things get stuck. In the initial call (20 minutes) we clarify goal, scope and start date.
First want to see what depends on what? IT landscape analysis with COMPIDDA · Is the database slowing you down? Database optimisation