Data engineering·Modelling for analysis
the same data exists three times: exactly as it arrived, cleaned and typed, and shaped for a specific report.
Medallion architecture
Also calledbronze silver gold, multi-hop architecture
Layering a lakehouse into raw arrivals, cleaned and conformed tables, and business-level aggregates. The value is that each layer has one job and one class of failure, so a bad number can be traced by walking down the layers, and reprocessing can start from any of them. The failure mode is ceremony — three copies of a table that only ever gets renamed — which is why the middle layer has to actually do conforming rather than just casting.