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Siebel Data Warehouse Requirements

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The Siebel Data Warehouse is a database that contains the star schemas created by Informatica. Although it is technically possible to put the Siebel Data Warehouse in the same database as the Siebel Transaction Database, it is not recommended for performance reasons. The Siebel Transaction Database is structured as an Online Transaction Processing (OLTP) database, whereas the Siebel Data Warehouse is structured as an Online Analytical Processing (OLAP) database. Each is optimized for its own purpose. The reasons for not combining the two databases are:

The OLAP queries interfere with normal use of the OLTP, which is entering and managing individual transactions.
The data in an OLTP is normalized for update efficiency. Analytical queries join several normalized queries and will be slow (as opposed to prejoined, denormalized OLAP tables).
Historical data cannot be purged from an OLTP, even if not required for current transaction processing because you need it for analysis (as opposed to OLAP being the warehouse for historical as well as current data). This causes the OLTP to further slow down.
OLTP databases are tuned for one specific application and it is not productive to use these separate OLTP databases for analytical queries that usually span more than one functional application.
The OLAP database can be specifically tuned for the analytical queries and Extract-Transform-Load (ETL) processing. These are quite different from OLTP requirements.
The Siebel Data Warehouse repository stores all of the Informatica object definitions for the ETL mappings that populate the Siebel Data Warehouse. It is a series of repository tables that are stored in a database, which can be the OLTP, OLAP, or a separate database.

The Siebel Data Warehouse works with native database management systems (DBMS). In addition to the general requirements, there are additional DBMS-specific requirements depending on the DBMS you are using.

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