Monday 18 March 2013

Implementing SCD type 1 (Slowly changing Dimensions) in Talend Open Studio

Today, I am going to implement Slowly Changing Dimensions (SCD) using Talend Open Studio. SCD are the dimension attributes whose values may change over time. E.g. Address, Marital Status etc.
There are three types of SCD:
SCD Type 1 :- Do not store any historical changes for the dimension attribute.
SCD Type 2 :- All historical changes will be stored for the dimension attribute.
SCD Type 3 :- Not all historical changes will be stored for the dimension attribute.only Previous value will be stored in the dimension table.

Summary of Slowly Changing Dimension Type 1
1. No historical changes for the dimension attribute is stored in Dimension Table. Old value will be over written with Changed value.
2. No new columns needs to be added to Dimension table.
3. No new record will be inserted in the Dimension table for every change in the dimension attribute. Hence, Primary Key and Surrogate Key remains the same.

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  1. Thanks Vikram for this new was helpful..the only problem I see here is video everything was just perfect..thanks for this.

    -Pankaj K

  2. Thanks Pankaj, You are right, from now onwards I will post a better quality video.

    In fact I have already uploaded a video for SCD type 2 which has better quality. Visit

    Also, change the quality of video to higher quality in the setting options of you tube player.

    Vikram Takkar