reading data from a database

putting the data into the data warehouse

converting the extracted data from its previous form into the form in which it needs to be so that it can be placed into a data warehouse or simply another database

transition of the data before it is put into the data warehouse

converts data as obtained from sources into structures conforming to the common, unified data model

using transformational tools to extract data from operational system

extraction of new/modified/deleted data from sources insertion into staging area (or directly into data warehouse)

using manual techniques to extract the data

Source identification

Extraction frequency

Job sequencing

Transformation method

identify source applications and source structures

determine how to handle input records that cannot be extracted

determine whether the beginning of one job in an extraction hob stream has to wait until the previous job has finished successfully

for each data source, denote the time window for the extraction process

Selection

Splitting/Joining

Enhancement

Summarization

Applying ongoing changes as necessary in a periodic manner

Populating all the data warehouse tables for the very first time

Completely erasing the contents of one or more tables and reloading with fresh data

If the primary key of an incoming record matches with the key of an existing record, update the matching target record. If the incoming record is a new record without a match with any existing record, add the incoming record to the target table.

If the primary key of an incoming record matches with the key of an existing record, leave the existing record, add the incoming record, and mark the added record as superseding the old record

When an incoming record is a duplicate of an already existing record, you may define how to handle an incoming duplicate - the incoming record may be allowed to be added as a duplicate or may be rejected during the append process

If the target table to be loaded already exists and data exists in the table, the load process wipes out the existing data and applies the data from the beginning

complete reload at specified intervals

application of incremental changes in the data sources

The load function that writes the resulting data