Chapter 5. Loading Data into the Warehouse

The ETL Process

Populating a data warehouse involves all of the tasks related to getting the data from the source operational systems, cleansing and transforming the data to the right format and level of detail, loading it into the target data warehouse, and preparing it for analysis purposes.

Figure 5.1 shows the steps making up the extraction, transformation, and load (ETL) process. Data is extracted from the source operational systems and transported to the staging area. The staging area is a temporary holding place used to prepare the data. The staging area may be a set of flat files, temporary staging tables in the Oracle warehouse, or both. The data is integrated with other data, cleansed, and transformed ...

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