SAP BW

1.0 Introduction

In the fiercely increasing competition amongst corporations it has become mandatory to make quick and sound crucial business decisions based on analysis of business critical data. This is the point where data warehouses come into play. Although many companies are relying on data warehouses, they are still struggling to achieve positive results due to fragmented and inconsistent data. For them SAP’s Business Information Warehouse (BW) provides a complete information factory solution. BW is the central component in the SAP suite of applications with an added advantage of being a software package that can be used in both SAP and non-SAP environments.
2.0 SAP’s BW Information Model: Overview
SAP’s BW information model is based on the core building block of InfoObjects which are used to describe business processes and information requirements. They provide basis for setting up complex information models in multiple languages, currencies, units of measure, hierarchy, etc. The key elements in the SAP’s BW information model are:
• DataSources
• InfoSources
• ODS Objects
• InfoCubes
• InfoProviders
• MultiProviders
Data Sources
DataSources are flat data structures containing data that logically belongs together. They are responsible for extracting and staging data from various source systems.
InfoSources
InfoSources are the group of InfoObjects that belong together from a business point of view. It contains the transactional data obtained from the transactions in online transactional processes (OLTP) and master data such as addresses of customers and organizations, which remain unchanged for longer time period.
ODS objects
An ODS object is a dataset which is formed as a result of merging data from one or more info sources. In it information is stored in the form of flat, transparent database tables that are used for preparing reports and quality assurance purposes.
InfoCubes
InfoCubes are multidimensional data storage containers for reporting and analysis of data. They consist of keys figures and characteristics of which latter is organized as dimensions facilitating users to analyze data from various business perspectives such as geographical area or types of sales channel.
InfoProviders
InfoProviders refer to all the data objects that are present in the SAP BW systems. These include all the data targets viz. InfoCubes, ODS objects and master data tables along with Info sets, remote Infocubes and MultiProviders.
MultiProviders
MultiProvider is a virtual information provider which is a combination of any two physical or virtual info providers. MultiProviders do not contain any data and are used to combine data from different info providers. Their main purpose is to make this data accessible for reports and analysis.
3.0 Analytical View of Business Information Warehouse Model
SAP’s BW is based on "Enhanced Star schema" or "Info Cubes" database design. This database design has a central database table, known as ‘Fact Table’ which is surrounded by associated dimension tables. These dimension tables contain references to the pointer tables that point to the master data tables which in turn contain Master data objects such as customer, material and destination country stored in BW as Info objects. An InfoObjects can contain single field definitions such as transaction data or complex Customer Master Data that hold attributes, hierarchy and customer texts that are stored in their own tables.
Read This Nugget
The BW product is designed to store all business-critical information contained in the R/3 OLTP (online transaction processing) system and other non-SAP systems in a form that is easy to access and analyze using the BW client tools.
The database design used to meet these objectives is an "Enhanced Star Schema" or "InfoCube" (the data against which the end user runs queries).
The info cubes and master data tables that are used in a BW system are generally unique to that system as shown in the figure below:
Figure: SAP BW Database Design

The complexity of the objects in this design leads to the challenge of maintaining up-to-date and accurate data in all the BW data tables. However, loading data into the BW is accomplished by using InfoPackages. InfoPackages are tools for organizing data requests that are extracted from the source system and are loaded into the BW system. With the progress of BW project the number of info packages increases emphasizing the importance of good performance of each info package. Although the DBMS underlying the BW system is monitored by the standard software’s for the R/3 functionality but this leaves a gap between the table spaces and table names as they appear at the DBMS level and the BW application level entities to which these objects belong. To bridge this gap, the new BW functionality for R/3 includes reports that place DBMS objects in a BW context. These reports allow the user to take an object at the DBMS level and associate it with its application-level entity.
In case of any problem in order to enable the administrator to identify the problem the InfoPackages are organized on the basis of the object to which they are transporting data- Info cube, ODS or Master Data. The overall request status for the object is displayed, and an alarm is triggered if any Info Package run from any Info Source fails. In this way, the administrator is able to locate the exact position where a failure is going to impact the users and the BW system. Also, for InfoCubes, Master Data and the ODS to give an overview of the history of requests for the system, the progress of the last N requests through each stage of extraction and load is displayed, and for any failures, the step that failed is displayed. The performance of requests can be monitored by display of performance statistics for each stage of extraction and load in the form of graphs.
4.0 Building SAP BW into multi-tier architecture model in Business Services
Being implemented on top of SAP Web Application Services SAP’s BW provides a multi-tier architecture (figure shown below), along with a complete software development environment, system management tools and additional functionalities such as currency conversion or security. Although it is closely related to SAP R/3, SAP BW is a completely separate software package which comes with automated extraction and loading facilities.
Components of BW architecture
SAP BW is based on integrated metadata concept with metadata being managed by metadata services. SAP’s BW has following layers:
• Extraction, Loading and Transformation (ELT) services layer.
• Storage services layer, with services for storing and archiving information.
• Analysis and access services layer, which provides access to the information stored in SAP BW.
• Presentation services layer, which offers different options for presenting information to end users.
• Administration services.
• Metadata services.
Figure: Multi-tier Architectural Pattern


SAP BW Business Warehouse
- Metadata Modelling -

The administration services in SAP BW can be availed through Administration Workbench (AWB). It is a single point of entry for data warehouse development, administration and maintenance tasks in SAP BW with Metadata modeling component, scheduler and monitor as its main components as described in the figure hereunder:
Figure: Metadata Services Architecture

Metadata modeling: Metadata modeling component is the main entry point for defining the core metadata objects used to support reporting and analysis. This includes everything from defining the extraction process and implementing transformations to defining flat or multidimensional objects for storage of information.
Modeling Features
• Metadata modeling provides a Metadata Repository where all the metadata is stored and a Metadata Manager that handles all the requests for retrieving, adding, changing, or deleting metadata.
• Reporting and scheduling mechanism: Reporting and scheduling are the processes required for the smooth functioning of SAP BW. The various batch processes in the SAP BW need to be planned to provide timely results, avoid resource conflicts by running too many jobs at a time and to take care of logical dependencies between different jobs. These processes are controlled in the scheduler component of AWB. This is achieved by either scheduling single processes independently or defining process chains for complex network of jobs required to update the information available in the SAP BW system. Reporting Agent controls execution of queries in a batch mode to print reports, identify exception conditions and notify users and pre compute results for web templates.
• Administering ETL service layer in multi- tier level: SAP’s ETL service layer provides services for data extraction, data transformation and loading of data. It also serves as the staging area for intermediate data storage for quality assurance purposes. The extraction technology of SAP BW is supported by database management systems of mySAP technology and does not allow extraction from other database systems like IBM, IMS and Sybase. It does not support dBase, MS Access and MS Excel file formats. However, it provides all the functionality required for loading data from non- SAP systems as the ETL services layer provide open interfaces for loading non-SAP data.

Fundamentals of ETL Service Architecture
ETL service comprises of two parts: Staging engine and Storage Service. Staging engine manages staging process for all data received from several source systems. It interfaces with the AWB scheduler and monitor for scheduling and monitoring data load processes. However, Storage Service manages and provides access to data targets in SAP BW and the aggregates that are stored in relational and multidimensional database management systems.
It is true, however, that the extraction technology provided as an integral part of SAP BW is restricted to database management systems supported by mySAP technology and that it does not allow extracting data from other database systems like IBM IMS and Sybase. It also does not support proprietary file formats such as dBase file formats, Microsoft Access file formats, Microsoft Excel file formats, and others. On the other hand, the ETL services layer of SAP BW provides all the functionality required to load data from non-SAP systems in exactly the same way as it does for data from SAP systems. SAP BW does not in fact distinguish between different types of source systems after data has arrived in the staging area. The ETL services layer provides open interfaces for loading non-SAP data.
Extraction at Service Levels
SAP BW can be integrated with other SAP components based on application programming interface (API) service. It provides a framework to enable comprehensive data replication based on data extractors that encapsulate the application logic. Data Extractor fills the extract structure of data source with a data from data source and offers sophisticated handling of changes. In addition to supporting extractors, the service APIs also enable online access via RemoteCube technology and flexible staging for hierarchies. On the other hand SAP provides an open interface called Staging Business Application Programming Interface (BAPI) to extract data from non-SAP sources. BAPI serves the purpose of connecting third- party ETL tools to SAP BW and provides access to SAP BW objects which facilitates use of customer extraction routines. Data can be extracted at the database level by using: DB connect, flat files and XML. DB connect facilitates extraction directly from DBMS. In this the metadata files are loaded by replicating metadata tables and views into the metadatory repository of SAP BW. Data can also be uploaded from flat files by creating routines for extraction of data and XML files can be extracted through XML via Administrator Workbench in SAP BW.
Read This Nugget
SAP BW provides three ways to extract data at the database or file level: DB Connect, flat file transfer, and XML. SAP BW provides flexible capabilities for extracting data directly from RDBMS tables using DB Connect.

SAP BW Business Warehouse
- ETL Components -

Components of ETL Services at Database of File Level
• Operational Data Store: It stores detailed data and supports tactical, day-to-day decision making. A SAP view ODS as a near real-time informational environment that supports operational reporting by interacting with existing transactional systems, data warehouses, or analytical applications. SAP BW allows flexible access to data in the ODS, the data warehouse, and the multidimensional models.

• Data Marts: A data mart provides the data needed by a decentralized function, department, or business area. You need to weight the pros and cons before developing a data mart. For example, a data mart can be implemented faster and cheaper than a data warehouse, sometimes costing 80% less than a full data warehouse. But as data marts proliferate, the cost advantages can disappear. The IT organization must maintain the individual data marts and the multitude of ETL and warehouse management processes that go with them. Multiple data marts can complicate data integration efforts, increase the amount of inconsistent data, require more business rules, and create the data stovepipes that data warehousing strives to eliminate.

• Interfaces: The data mart interface enables users to transfer and update transactional data and metadata from one SAP BW system to other SAP BW systems.

• Open Hub Services: The open hub service is used to share data in SAP BW with non-SAP data marts, analytical applications, and other applications. This service controls data distribution and maintains data consistency across systems. With the open hub service, actual data and the corresponding metadata are retrieved from InfoCubes or ODS objects.


SAP BW Business Warehouse
- Storage Service Layers -

Understanding the role of storage services layers in architectural model
• Master data manager: Master Data Manager generates the master data infrastructure containing master data tables as well as master data update and the retrieval routines. It also maintains master data and provides access to master data for use by SAP BW reporting components and for exporting to other data warehouse services for analysis and access services.

• ODS Manager: ODS manager generates ODS data object infrastructure. It maintains an active data table for maintaining ODS object data, a change log for every update applied to the ODS object data as part of application process and provides access to ODS object data for SAP BW reporting and analysis functionality.

• Archiving Manager: The Archiving Manager stores unused, dormant data in an archive with the help of Archive Development Kit (ADK). ADK is connected to the SAP BW via Archiving Manager. It also keeps track of relevant metadata such as Infocubes and ODS objects which possibly will change over time.

• InfoCube Manager: It serves the function of generating the InfoCube Meta tables. It maintains InfoCube data tables and provides access to InfoCube data tables for SAP BW reporting and analysis.

SAP BW Business Warehouse
- Integration -

5.0 Analysis of BW support navigation facilities integrated to BW 3.0

OLAP BAPI: SAP BW 3.0 comes with the OLAP BAPI Interface (OBI) which provides functions that can be used by third party reporting tools to access BW Info cubes. It provides an open interface to access any information that is available through OLAP engine.
Integrating with XML: OLAP BAPI serves as the basis for the SAP implementation of XML for analysis. It is an XML API based on Simple Object Access Protocol (SOAP) designed for standardized access to an analytical data provider over the web. The XML interface introduced with SAP BW 3.0 release accepts XML data streams compliant with the SOAP. Unlike all other SAP BW interfaces in XML interface the actual data transfer is initiated by the source system.
Open Hub Services: The Open Hub Service allows controlled distribution of consistent data from any SAP BW InfoProvider to flat files, database tables and other applications with full support for delta management, selections, projections and aggregation. Open Hub Services have InfoSpokes as their core metadata objects. With the SAP 3.0 release InfoSpokes have become generally available.
Content Management Framework: The SAP Web Content Management Server stores unstructured information that users can go through and use efficiently. Integration with the SAP BW content management framework provides an integrated view on structured and unstructured information to the end user.

6.0 Conclusion

With the growing network of processes and systems, the need for efficient management support systems is also increasing. However for this it is not enough to place a company strategically and give guidelines for its further development. Instead it is essential to have real time analysis and graphical visualization of the key performance indicators. In SAP BW automatic assimilation and analysis of information is possible. BW gives a holistic view of the company by considering both the financial data and non- financial assets of the company. As corporate planning is often not done in one common planning tool (e.g. turnover plan in a sales system and cost center plan in excel) studying interdependencies and coordination among them has become even more tedious. Thus the strategic management system must establish a planning process through all levels of planning in the company to make the data available for all responsible persons in one system. With SAP BW it is possible to upload data of different planning tools, manipulate planning data and write back changed data to the operational system. SAP BW can also be used as early warning system to inform the responsible persons about critical indicators on the basis of already defined thresholds of these indicators.

7.0 Outlook

SAP BW has the usual data warehouse layers accompanied by administrative services through the Administrative Workbench. It allows exchange of data and metadata with other systems and tools in the case of SAP-specific interfaces like Staging BAPI and the OLAP BAPI and supports other industry standard interfaces allowing easy access to data and metadata maintained in SAP. Also, the metadata objects that are available in SAP BW are used to build Operational data stores, data warehouses and info marts. Thus, the services provided by SAP with SAP BW makes it a major tool for complete corporate information and strategy management.