How do I use SCD Type 2 in Datastage?
Read the incoming records through any input stage like sequential file/dataset/table. Do the required processing for the incoming data. After the above processing step, pass the data into the change capture stage.
What is SCD in Datastage?
SCD’S is nothing but Slowly changing Dimensions. Slowly Changing Dimensions are the dimensions that have the data that change slowly rather than changing in a time period, i.e regular schedule. The most common Slowly Changing Dimensions are three types.
How many types of SCD we can implement using Datastage SCD stage?
“It is processing stage, that it applies the changes of records of a table”. Table: this table is describing the SCD six types and the description is shown above.
What is SCD1 and SCD2?
SCD Stands for Slowly changing dimensions. SCD1: only maintained updated values. Ex: a customer address modified we update existing record with new address. SCD2: maintaining historical information and current information by using. A) Effective Date.
How do you implement SCD Type 3 in DataStage?
To implement SCD Type 3 in Datastage use the same processing as in the SCD-2 example, only changing the destination stages to update the old value with a new one and update the previous value field.
How do you implement SCD Type 3 in Datastage?
What are the different types of Scds used in data warehousing?
Very simply, there are 6 types of Slowly Changing Dimension that are commonly used, they are as follows:
- Type 0 – Fixed Dimension. No changes allowed, dimension never changes.
- Type 1 – No History.
- Type 2 – Row Versioning.
- Type 3 – Previous Value column.
- Type 4 – History Table.
- Type 6 – Hybrid SCD.
What is a Type 2 SCD?
Type 2 SCDs – Creating another dimension record. A Type 2 SCD retains the full history of values. When the value of a chosen attribute changes, the current record is closed. A new record is created with the changed data values and this new record becomes the current record.
How do you test for SCD Type 2 in ETL Testing?
Below are the steps :
- Create a Component test case and take a snapshot of the current values in the EMPLOYEE_DIM (called Baseline).
- Modify a few records in the source EMPLOYEE table by updating the values in the key columns such as SALARY, LAST_NAME.
- Execute the ETL process so the the EMPLOYEE_DIM has the latest data.
Which SCD type is better?
For dimensions, you need to decide which columns can change, and whether you need to know their previous value. If none of the columns can change, then SCD0 is usually the most appropriate.
What is the difference between SCD2 and SCD3?
Difference : SCD2 is unlimited history and SCD3 is limited history. Explanation: 1- Using SCD2 you can save unlimited history with the help of the Surrogate Key .