A dynamic cache is a cache that the Integration Service updates when it processes each row. Use a dynamic lookup cache to keep the cache synchronized with the target.
You can use a dynamic cache with a relational lookup and flat file lookup. The Integration Service builds the cache when it processes the first lookup request. It queries the cache based on the lookup condition for each row that passes into the Lookup transformation. The Integration Service updates the lookup cache when it processes each row.
Based on the results of the lookup query, the row type, and the Lookup transformation properties, the Integration Service either inserts or updates rows in the cache, or makes no change to the cache.