What is duplicate detection during extraction?

< 1 min read

Duplicate detection during extraction means identifying repeated records before loading to the model.
Duplicates usually occur due to API retries or incremental load overlaps.
In my project, same Order ID appeared twice during daily refresh.
We used composite key (OrderID + LineID) to detect uniqueness.
Power Query grouped records and kept latest record based on timestamp.
SQL staging table also had DISTINCT and primary key constraints.
Duplicate rows were logged into an audit table for analysis.
This prevented double counting in revenue dashboards.
Row count reconciliation confirmed corrected totals.
So duplicate detection protects report accuracy and business decisions.

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