When you enable Insert Else Update, the Integration Service inserts a row with the expression result if the data is not in the cache. The lookup port value is NULL when data does not exist in the cache. If the expression refers to the lookup port value, the Integration Service substitutes the default port value in the expression. When you enable Insert Else Update and the data exists in the cache, the Integration Service updates the cache with the expression result.

When you enable Update Else Insert, the Integration Service updates the cache with the expression result if the data exists in the cache. When the data does not exist in the cache, the Integration Service inserts a row that contains the expression result. If the expression refers to a lookup port value, the Integration Service substitutes the default port value in the expression.