Early arriving fact is a natural thing in data warehouse and we have to understand it and handle it. This article is related to it. Hope it will be interesting.
What is Early Arriving Facts
As named says the Fact table data is arrived early where we do not have any dimension data. That means when we are going to lockup Fact table by the natural key of fact table with surrogated key of Dimension table we are not finding anything.
What the reason of Early Arriving Facts
There is several reason of early arriving fact described
- It’s according to system or scenario design like that the data of the fact table is arrived before the dimension data. If we take a suitable example: suppose at hospital if the patient in critical position then the operational or treatment data is gathered in fact first and then it going to gather the dimension data like patient details.
- If the Dimension data came from Master and Fact data came from Transaction table and the fact data is gather first in a point of time.
- If the ETL fails when loading the Dimension data.
How to Solve it
One of the common solutions is to implement the Inferred member when processing Dimension by ETL process.
An inferred member is a dimension row that has been created as a result of an early arriving fact. The inferred member will have the natural key from the fact table and default values for the rest of the columns. We probably want to add an indicator column in the dimension to identify the row as an inferred member by using a bit column called Inferred Member
Hope you like it.
Posted by: MR. JOYDEEP DAS