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6.3\9 SSIS 2008R2_Training - SCD Transformation


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This PPT explains SSIS Data flow task transformation that exists in SQL Server 2008 R2, it's the continuation of "" PPT.

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6.3\9 SSIS 2008R2_Training - SCD Transformation

  1. 1. . @copyright 2014 ( Presented by: Pramod Singla
  2. 2. Fact Tables 1. SCD Type 1 It is used when there is no need to store historical data in the dimension table. This method overwrites the old data in the dimension table with the new data. It is used to correct data errors in the dimension. 2. SCD Type 2 It stores the entire history the data in the dimension table. With type 2 we can store unlimited history in the dimension table. In type 2, you can store the data in three different ways. They are • Versioning • Flagging • Effective Date 3. SCD Type 3 only the current status and previous status of the row is maintained in the table. To track these changes two separate columns are created in the table. Slowly Changing Dimensions (SCD) - Types @copyright 2014
  3. 3. Fact Tables • It coordinates the updating and inserting of records in data warehouse dimension tables • only supports connections to SQL Server • The Slowly Changing Dimension transformation supports four types of changes – changing attribute (equivalent to a Type 1 change) – historical attribute (equivalent to a Type 2 change) – fixed attribute – inferred member • Type 3 changes not supported in SCD. • The Slowly Changing Dimension transformation has one input and up to six outputs. – Fixed Attribute Output and Unchanged :No default data flow is created automatically. SCD Tool in SQL Server @copyright 2014
  4. 4. SCD Data Flow Diagram Source Incoming Records SCD Look up Table row contains changes New Output Record Found?No Yes No Unchanged Output identifies the update type Yes Changing Attributes Updates Output Historical Attributes Inserts Output Fixed Attribute Output Inferred Member Updates Output Destination historical attribute changing attribute fixed attribute historical attribute @copyright 2014
  5. 5. @copyright 2014 (
  6. 6. Resources & Questions • Contact me : – – • Microsoft Resources: – – – – @copyright 2014