What r the mapings that we use for slowly changing dimension table?

hello sir,

i want whole information on slowly changing dimension.and also want project on slowly changing dimension in informatica.

Thanking you sir,

mamatha.

1.Up Date strategy Transfermation

2.Look up Transfermation.

Type1: Rows containing changes to existing dimensions are updated in the target by overwriting the existing dimension. In the Type 1 Dimension mapping, all rows contain current dimension data. Use the Type 1 Dimension mapping to update a slowly changing dimension table when you do not need to keep any previous versions of dimensions in the table. Type 2: The Type 2 Dimension Data mapping inserts both new and changed dimensions into the target. Changes are tracked in the target table by versioning the primary key and creating a version number for each dimension in the table. Use the Type 2 Dimension/Version Data mapping to update a slowly changing dimension table when you want to keep a full history of dimension data in the table. Version numbers and versioned primary keys track the order of changes to each dimension. Type 3: The Type 3 Dimension mapping filters source rows based on user-defined comparisons and inserts only those found to be new dimensions to the target. Rows containing changes to existing dimensions are updated in the target.

SCD:

Source to SQ - 1 mapping,

SQ to LKP - 2 mapping,

SQ_LKP to EXP - 3 Mapping,

EXP to FTR - 4 Mapping,

FTR to UPD - 5 Mapping,

UPD to TGT - 6 Mapping,

SQGen to TGT - 7 Mapping.

I think these are the 7 mapping used for SCD in general;
For type 1: The mapping will be doubled that is one for insert and other for update and total as 14.
For type 2 : The mapping will be increased thrice, one for insert, 2nd for update and 3 to keep the old one. (here the history stores)
For type three : It will be doubled for insert one row and also to insert one column to keep the previous data.

Cheers
Prasath

The Dimensions are classified 3 types.

1.SCD TYPE1 (Slowly Changing Dimension) : contains current data.

2.SCD TYPE2 (Slowly Changing Dimension) : contains current data + complete
historical data.

3.SCD TYPE3 (Slowly Changing Dimension) : contains current data + recent
historical data.