Engineering – Databases, Backend & Data Integration

When data volumes grow, interfaces multiply and performance becomes critical, you don’t need buzzwords – you need solid architecture, reliable data models and clean implementation. I support you hands-on in building, modernizing and stabilizing systems – with a strong focus on SQL databases, backend development (Java/Python), and integration across heterogeneous environments.

What I deliver

From “it works” to “it runs fast, stable, and maintainable”

Service areas:

SQL & Databases: data modeling, query optimization, performance tuning, indexing/statistics strategies, troubleshooting.
Data Integration & ETL/ELT: extraction from source systems, transformations & data-quality rules, consistent target models, automated pipelines.
Backend Development: services, APIs, batch processing, data-access layers – designed for testability and smooth deployments.
Modernization: refactoring, replacing legacy components, migrations (DB/application), reducing technical debt.
Operational Stability: build/deploy setups, pragmatic observability/monitoring, production-grade support processes.

Focus areas

1) SQL Databases – Performance & Data Quality

Many issues are not caused by “the code”, but by data access patterns, schema design and execution plans. I help you identify bottlenecks systematically (measurement first), isolate root causes and implement sustainable fixes – without trial & error.

Analysis of slow queries, locks, wait events, plan regressions
Index and schema optimization, data model reviews
Data-quality rules, plausibility checks, reproducible reporting

2) Integration – Connecting heterogeneous systems properly

Whether it’s legacy applications, line-of-business systems, clinical systems or modern web services: the key is a clear target model, explicit transformation logic and a pipeline that runs reliably and is well documented.

ETL/ELT pipelines, mapping, consolidation
Versioned rules (e.g., definitions/value ranges) and traceable changes
Exports, reports and downstream interfaces aligned with business definitions

3) Backend & Web – Java / Python

I build and stabilize backend components with a focus on maintainability, testability and clear interfaces – from established Java stacks to Python web frameworks – aligned with your existing environment.

Java (incl. J2EE environments, services, persistence, integrations)
Python (Django/Flask/Tornado – depending on requirements)
API design, auth, data access, jobs/batch, error handling and logging strategies

4) Healthcare IT – HL7 / FHIR / Mirth

In healthcare environments, traceability, standards compliance and robust integration logic matter. I support connectivity, processing and testability of messages and profiles – practical and operations-ready.

Interoperability and integration using HL7 / FHIR
Integration and routing scenarios (e.g., via Mirth)
Experience with typical hospital IT landscapes

Technologies (selection)

Platforms: Windows, macOS, Linux (Debian/Ubuntu)
Virtualization/Environments: Proxmox, VMware, KVM, VirtualBox
SQL: MySQL, PostgreSQL, MS SQL Server, Oracle (also Sybase/Informix/SQLite)
NoSQL/Storage/Formats: Redis, Cassandra, HDF5, Parquet; Object Storage (e.g., MinIO)
Data/Processing: Pandas, Dask, PySpark, NumPy
Frontend (if required): HTML5, Vue/Vuetify, Quasar

How I work

1) Rapid assessment: goals, bottlenecks, data flows, risks – what is “definition” vs. what is “defect”?
2) Target picture & priorities: measurable criteria (performance, quality, stability) and a pragmatic roadmap
3) Delivery: iterative, transparent, with documentation/tests where it makes sense
4) Handover & enablement: knowledge transfer, pairing, maintainability and operations guidelines

Typical outcomes

Performance report (findings + actions + measurable before/after impact)
Data model or interface concept incl. mapping/transformation logic
ETL/ELT pipeline incl. data-quality checks and logging
Production-ready backend service (API/jobs) incl. deployment and operating setup

FAQ

Do you also handle urgent troubleshooting?
Yes – structured and focused on sustainable fixes (measure → root cause → fix → safeguards).
Remote or on-site?
Both are possible – depending on the project and collaboration needs.
How does contracting work?
I often deliver the work personally in projects (freelance/interim). Contracting and invoicing can – depending on your preference – be handled via ISCaD GmbH.

Want to discuss a concrete project (performance, integration, modernization, healthcare interoperability)? Feel free to contact us by email.