Teradata to Hadoop migration with SCD Type 2 requires careful planning. Key steps: (1) Schema mapping—map Teradata tables to Hive/Spark equivalents; handle Teradata-specific functions. (2) SCD Type 2 logic—maintain current and historical rows using effective_date, effective_end_date, and is_current flag. In Spark: use MERGE (Delta) or upsert logic with window functions to detect changes. (3) Migration strategy—batch historical load first, then CDC for ongoing changes....
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