This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
1
SAP BW Data Modeling
SAP University AlliancesVersion 2.0Authors Klaus Freyburger
• InfoObjects are the “bricks” to build data structures inside SAP BW.– InfoObjects represent business objects from an end user’s
view.– The most important InfoObject types used for business analysis
are Characteristics and Key Figures.
SAP BI Curriculum BI2-M2 SAP BW Data Modeling
SAP UA
InfoObject: Characteristics
• A Characteristic represents a business object (or concept, business term, business entity).– A Characteristic may have attributes which describes the
business object in more detail.– Example: InfoObject “Customer” is a characteristic with
attributes such as “Customer Number”, “ZIP Code”, “Region”,
– The attributes “Customer Number”, “ZIP Code”, “Region”, etc. are also managed as Characteristics and may have their own attributes.
Note: What SAP calls a Characteristic is often referred to in the data warehouse community as a Dimension.
3
SAP BI Curriculum BI2-M2 SAP BW Data Modeling
SAP UA
InfoObject: Key Figures
• A Key Figure (or variable, measure) is oftenly used to document the performance of a business process over time.– It can be found in document records such as invoice, delivery
note, purchase order, or goods receipt.– Example: InfoObject “Revenue” or “Sales Amount”, etc.
• Note: InfoObjects are unique inside SAP BW, and they are used to build the data structures for analysis requirements.– Conceptually unique: the semantics (meaning) of an
InfoObject is uniquely defined system-wide inside SAP BW.– Logically unique: the data type, value range or field length is
uniquely defined system-wide inside SAP BW.– From the technical point of view, an InfoObject can viewed as a
database field.
SAP BI Curriculum BI2-M2 SAP BW Data Modeling
SAP UA
Evolution from a SAP ERP Database Object to an SAP BW InfoObject
InfoProviders:• Are data storage inside SAP BW• May store data records physically (persistent)• May also be used to access data stored outside SAP BW virtually
(transparent views)• May be accessed with front end tools such as SAP
Use star database schema, consisting of a fact table surrounded by dimension tables.
• Use a maximum of 3 + 13 dimension tables.– 3 dimension tables are pre-defined by SAP.
• Time, Unit and DataPackage (for technical information)– 13 dimensions may be used by InfoCube developers.
Note: In practice, good InfoCube design should not exceed 6-8 dimensions (+ the 3 above) so 13 dimensions are plenty.
5
SAP BI Curriculum BI2-M2 SAP BW Data Modeling
SAP UA
DataStore Objects
• Contain single data records such as invoices, purchase orders or customer order items.
• Consist of key fields (such as “order number”, “order position number”) and data fields (Key Figures and Characteristics such as “sales amount”, “ net value”, “customer id”, “material number”).
Reference Characteristic, e.g. QuarterThe reference characteristic allows the use of a function to aggregate data instead of summation.Example: Number of Employees at the end of the quarter. Sum does not make sense!
7
SAP BI Curriculum BI2-M2 SAP BW Data Modeling
SAP UA
Key Figure Definition: Revenue (cont.)
If the Key Figure is non-cumulative (e.g., warehouse stock), this field defines an InfoObject representing non-cumulative change. This
• Numeric values are stored in natural order in database, e.g. 0002 first, then 0010
Material Group in SAP Business Content has numerical values with trailing blanksConversion exit ALPHA must not be used
SAP BI Curriculum BI2-M2 SAP BW Data Modeling
SAP UA
MATN1 Conversion Routine
Database field Material often requires special treatment.• Datatype CHAR in SAP• Conversion exit MATN1 is used• Edit format can be defined in transaction OMSL
– E.g. _ _-_ _ _ _ User Input RB-0010 is stored as RB0010
• Units and Currencies are used to define Key Figures in more detail.• A Unit may be an InfoObject which defines the Unit of a Key Figure.• A Currency may be an InfoObject which defines the Currency of a
7 Steps to Define an InfoCube1) Choose a name for an InfoCube2) Create Dimensions as needed3) Assign Characteristics to Dimensions4) Choose Time Characteristics5) Choose Key Figures
3. Navigation Attributes are ready to be used in analysis.
SAP BI Curriculum BI2-M2 SAP BW Data Modeling
SAP UA
Steps to Create an InfoCube
• Define the InfoObjects needed.– Key Figures– Characteristices
• Define which Characteristics may be chosen to create a semantic cluster for semantic dimensions.– Examples are: Sales, Production, Material Management, Finance, etc.