What the work requires.
WHAT IS ESSENTIAL
SQL, thoroughly One programming language, usually Python Understanding of how databases work Version control Command line competence
WHY SQL FIRST
It is the common language of data, and most work is expressible in it.
WHAT ELSE MATTERS
Data modelling Understanding of distributed systems Scheduling and orchestration Cloud platform basics Testing practice
WHAT TOOLS EXIST, BY CATEGORY
Ingestion and connectors Transformation frameworks Orchestrators Warehouses and query engines Streaming platforms Quality and observability tools
WHAT TO BE CAREFUL WITH
Adopting many tools before establishing the need Tools requiring substantial operation for modest benefit
WHAT TO PREFER
Fewer tools, understood well.
WHAT MATTERS MORE THAN TOOLING
Whether the data is correct and arrives when expected.
WHAT EMPLOYERS ACTUALLY ASK ABOUT
SQL, modelling, and how you handled something that went wrong.
WHAT TO BUILD FOR A PORTFOLIO
A working pipeline, end to end, with tests and documentation.
