Big Data Series

SSDB – Part 4. ETL – Slowly Changing Dimension SCD Type 2 and 3

Tracking Changes over Time with SCD Type 2 and 3:

Incremental Loading

Incremental loading is an option that works well with large tables of data or when you wish to preserve the original values in your data.

Incremental loading compares values between the source and destination tables. Using that comparison, you can program the following tasks:

  • Add new rows that are found in the source but not in the destination
  • Update rows in the destination that are changed in the source
  • Delete (or flag) rows from the destination that are removed in the source

You can use a number of techniques to program these tasks. The SQL Merge command is the most efficient method.

Note: Microsoft is the owner of the content and video in this blog post.

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