Est. 2018Database Design & Architecture
Depth over shortcuts.
ZiRoqenl exists for people who want to understand databases — not just use them. We work with clients over months, not sessions, because real fluency in schema design and data modeling takes sustained effort.
The difference between a fragile database and a robust one is rarely a missing tool — it is usually a missing mental model.
Our approach is direct: we look at what you are building, identify where the design breaks under load or change, and work through the reasoning together until it holds.
When ZiRoqenl first opened its doors to mentorship clients
What we actually do
Focus area
Relational and non-relational database design, normalization, indexing strategy, and query performance
Most database problems arrive disguised as performance issues. A query runs slowly, a report takes minutes instead of seconds — and the instinct is to optimize the query. Usually the issue is upstream: a schema decision made early that forces every subsequent query to work harder than it should.
We spend time with clients tracing those upstream decisions. That means reading existing schemas together, discussing the tradeoffs behind each design choice, and rebuilding the mental model that leads to better decisions next time.
340+
Mentorship engagements completed since 2018
18 mo
Average duration of an active mentorship relationship
Every engagement starts with a schema audit — not a sales call. We need to see the actual structure before we can say anything useful.
How the mentorship runs
Three consistent practices that define every engagement — regardless of the client's starting point or database stack.
Schema review before anything else
Before the first session, you share your current schema. We map the relationships, flag normalization issues, and identify where growth will create friction. This gives the mentorship a concrete starting point rather than a generic curriculum.
Regular sessions with written follow-up
Sessions happen on a fixed cadence — weekly or biweekly depending on your pace. After each one, you receive a written summary of what was covered and what to work on next. The notes accumulate into a record of your progress.
Real problems, not exercises
We work on your actual database — a production schema, a migration you are planning, a performance issue you cannot explain. Constructed exercises have their place, but sustained understanding comes from solving problems that matter to you.
The people behind the sessions
ZiRoqenl is a small team. Every mentor has worked with production databases at scale — not just taught about them. That distinction matters when a client brings a real schema with real constraints.
Darko Veselinović
Lead Mentor
Darko spent nine years designing data models for logistics platforms across three continents. He joined ZiRoqenl in 2019 and now leads the curriculum for relational database engagements.
Oliwia Kasprzak
Mentor — NoSQL & Distributed Systems
Oliwia's background is in document databases and event-driven architectures. She works with clients who are moving from relational to distributed systems and need to rethink how they model data.
Taavi Leppänen
Mentor — Query Performance
Taavi focuses on indexing strategy and query execution plans. If a client's database is slow and nobody knows why, Taavi is usually the person who finds out — and explains it clearly enough that it does not happen again.