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# Parquet, Delta, Iceberg & Ducklake - An introduction for developers


- **Date:** Thursday, Jul 9, 2026
- **Time:** 13:30–14:00 (30 min)
- **Room:** Stage 12
- **Event:** World Congress 2026 Europe

## Recording

[Watch recording](https://www.wearedevelopers.com/videos/100075-parquet-delta-iceberg-ducklake-an-introduction-for-developers)

## Description

CSVs are inefficient. Everyone knows that. And yet they are probably the most widely used file formats, also for data scientists. At the same time, data engineers talk about Parquet, Iceberg, and Ducklake—and roll their eyes when someone actually still uses CSV or JSON.

As a software engineer, there's often nothing left to do but close your eyes and go for it. Even if you don't really understand it. You read CSV, you write Delta or Iceberg. The main thing is that the data guys don't complain. But what are the differences? Why do we store data in files in the first place? What is all this metadata? And what do I really need and what not? And why can't just look onto storage but also have to take the compute into account. It's high time to dive in.

## Speaker

### [Matthias Niehoff](https://www.wearedevelopers.com/@matthias-niehoff)

Head of Data at codecentric


## Related talks at this congress

- [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
- [TiDB, One Layer at a Time: How Distributed SQL Became an Agentic AI Backbone](https://www.wearedevelopers.com/events/world-congress-2026-europe/sessions/1119-tidb-one-layer-at-a) — Daniël van Eeden, Mattias Jonsson
- [From Messy Queries to Scalable Systems - How Data Engineering actually works](https://www.wearedevelopers.com/events/world-congress-2026-europe/sessions/1219-from-messy-queries) — Sandhya Menon
- [Beyond SQL Generation: How to Teach Agents What Your Database Actually Means](https://www.wearedevelopers.com/events/world-congress-2026-europe/sessions/1137-beyond-sql) — Celeste Horgan