From DataStage and Informatica to Databricks Medallion Architecture: Why Migration Is More Than Code Conversion (opens in new tab)

Legacy ETL modernization is often described as a technology migration. Move DataStage jobs to Databricks. Convert Informatica mappings into PySpark. Replace legacy workflows with notebooks and Delta tables. But that description misses the hardest part. The real challenge is not converting syntax. The challenge is understanding years of hidden transformation logic, reconstructing data lineage, separating technical processing from business logic, and deciding where each responsibility belongs i...