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# From Messy Queries to Scalable Systems - How Data Engineering actually works


- **Date:** Friday, Jul 10, 2026
- **Time:** 09:40–10:10 (30 min)
- **Room:** Stage 2
- **Event:** World Congress 2026 Europe

## Recording

[Watch recording](https://www.wearedevelopers.com/videos/100203-from-messy-queries-to-scalable-systems-how-data-engineering-actually-works)

## Description

I started my tenure at E.ON Energy Deutschland as a Business Analyst in a small BI team and currently am a lead Data engineer in the Data Engineering team. In my talk I would like to showcase the importance of Data Engineering and explore how ad hoc analytics at E.ON evolved into reliable data systems. I would like to uncover how good Data engineering practises turn ad hoc analytic queries into scalable data platforms and improve not just performance and cost but also collaboration, trust and developer experience.

## Speaker

### [Sandhya Menon](https://www.wearedevelopers.com/@sandhya-menon)

Lead Data Engineer at E.ON Energy Deutschland


## Related talks at this congress

- [Engineering Customer Journey Analytics at Scale: Lessons from Germany's Largest Banking Platform](https://www.wearedevelopers.com/events/world-congress-2026-europe/sessions/952-engineering-customer) — Jannis Eickenroth, Sophie-Theresa Kleinke, Yasmin Schneider, Peteris Dundars
- [Swapping a Data Warehouse at Runtime: Zero-Downtime Migration Without Changing a Single Client](https://www.wearedevelopers.com/events/world-congress-2026-europe/sessions/1345-swapping-a-data) — Max Fischer, Michael O'Toole
- [The Missing Layer Between Enterprise Data and AI Agents](https://www.wearedevelopers.com/events/world-congress-2026-europe/sessions/1328-the-missing-layer) — Jannis Eickenroth, Sebastian Klenke
- [Parquet, Delta, Iceberg & Ducklake - An introduction for developers](https://www.wearedevelopers.com/events/world-congress-2026-europe/sessions/1080-parquet-delta) — Matthias Niehoff