There are three types of Load Processing in Data Warehouse Administration(DAC).
- Post Load Processing (PLP)
- Source Independent Load (SIL)
- Source Dependent Extract (SDE)
Post Load Processing (PLP) mapping, which is used to load aggregate tables after target tables have been loaded.
This mapping is designed to be source independent.
After Loading from staging tables to target tables, the completed load of dimension and fact table then the aggregate tables will be extract and load in the target of data warehouse.
Source Independent Load (SIL) mappings – extracts and transforms data from the Staging tables and loads to the data warehouse target tables.
SIL mappings are designed to be universal with any source.
SIL_* – we can find two SIL_* and SIL_*_FULL workflows in the Workflow Manager.
There is two form of source independent load will work one is according to the full load of extraction and the other is incremental load of extraction and load from the staging tables to target tables.
SIL_* will load full load when there is no index, it loads the data from data source Staging tables to target tables of data warehouse using ETL process as DAC.
During a full load the workflow (SIL_*_Full) will be invoked from DAC and the target table is truncate ,indexes are dropped ,data is loaded in ‘Bulk’ mode and then the indexes are rebuild.
During incremental load, the workflow (SIL_*) will be invoked which would just insert/update the incremental data.
Since the amount of data during incremental load is minimal compared to full load this would run in ‘Normal’ mode.
If indexes are present on a table “BULK” mode does not work.
Work Flow of SIL:
In Informatica you can see the mappings of source independent load (SIL), for your reference see the below picture.
Source Dependent Extract (SDE) mappings – extracts the data from the transnational Source Systems and loads into the data warehouse staging tables.
SDE mappings are designed with respect to the source’s unique data model.
SDE_* workflows have only the staging table, the workflow will load the data into the staging area tables.
In the staging the tables will not have index.
It always truncates the data and loads the data into staging table.
So the load type will be BULK mode because the stagings have no indexes defined.
Work Architecture of SDE
In Informatica we can see the mappings with the name of SDE_*.For your Reference see the below Picture.
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