BW BW服务中间层所包含的组件的功能

Metadata Repository contains information about the data warehouse. Meta-data comprise data about data. Metadata Repository contains two types of meta-data: business-related (for example, definitions and descriptions used for reporting) and technical (for example, structure and mapping rules used for data extraction and transformation). We use Metadata Manager to maintain Metadata Repository.

Staging Engine implements data mapping and transformation. Triggered by BW Scheduler, it sends requests to a source system for data loading. The source system then selects and transfers data into BW.

PSA (Persistent Staging Area) stores data in the original format while being imported from the source system. PSA allows for quality check before the data are loaded into their destinations, such as ODS Objects or InfoCubes.

ODS (Operational Data Store) Objects allow us to build a multilayer structure for operational data reporting. They are not based on the star schema and are used primarily for detail reporting, rather than for dimensional analysis.

InfoCubes are the fact tables and their associated dimension tables in a star schema.

Data Manager maintains data in ODS Objects and InfoCubes and tells the OLAP Processor what data are available for reporting.

OLAP Processor is the analytical processing engine. It retrieves data from the database, and it analyzes and presents those data according to users' requests.

BDS (Business Document Services) stores documents. The documents can appear in various formats, such as Microsoft Word, Excel, PowerPoint, PDF, and HTML. BEx Analyzer saves query results, or MS Excel files, as workbooks in the BDS.

User Roles are a concept used in SAP authorization management. BW organizes BDS documents according to User Roles. Only users assigned to a particular User Role can access the documents associated with that User Role.