Scd's are the dimensions that have the data that changes slowly. Rather than
changing in a time period. That is a regular schedule.
The Scd's are performed mainly into three types.
Type -1 SCD: In the type -1 SCD methodology, it will overwrites the older data
( Records ) with the new data ( Records) and therefore it will not maintain the
This will used for the correcting the spellings of names, and for small updates of
TYpe -2 SCD: In the Type-2 SCS methodology, it will tracks the complete historical
information by creating the multilple records for the given natural key ( Primary
key) in the dimension tables with a separate surrogate keys or a different
version numbers. We have a unlimited historical data preservation, as a new
record is inserted each time a change is made.
Here we use differet type of options inorder to track the historical data of
a) Active flag
b) Date functions
c) Version Numbers
d) Surrogate Keys
We use this to track all the historical data of the customer.
According to our input, we use required function to track.
Type-3 SCD: In the Type-2 SCD, it will maintain the partial historical