Sap Notes On Delta

SAP Notes on DELTA : Delta Types : A term that describes how the data gets into the delta queue. Serialization: The sequence in which the data records arrive in BW. Record Mode : A description of the contents of a record. Delta Method : A term that classifies a data source according to record mode, serialization, and delta type. Update Mode : Specify the data that you want to request. Update mode “F” = full update: Available for all data sources. Update mode “C” = delta initialization • It the extractor supports deltas, it must be initialised prior to a delta run. • Selection conditions are saved. Finally a full upload is started for the selected range of data. Additional settings are saved to allow for future delta uploads. Update mode “D” = delta • If the extractor supports deltas, only new or changed records are sent. o E.g : FI, LO Uses V3 updates. Update mode “R” = repeat • Only if a delta is showing a RED traffic light status. • A dialog box prompts you to decide whether or not the last group of delta records needs to be reloaded. Update Mode “E” = Pulled Delta. • The data is pulled into the queue by the extractor program in delta mode. o E.g : LIS, CO-PA How does the data arrive in the delta queue ? Push Mode : In push mode, the application pushes the delta records directly into the delta queue when the transaction is saved. Pull Mode : In pull mode several BWs pull data from the delat queue on request. The only way to get data from historic applications without modifying the table structures.

Record Modes • • • • • •

Each record must be classified What did the record look like after the change image ? “After Image” = Record Mode “ “ What did the record look like before the change ? o “Before Image” = Record Mode “X”. Show only the difference for all numeric values. o “Additive Image” = Record Mode “A”. For each Change that is made, a new, unique record is generated. o “New Image” = Record Mode “N”. Only provide the key information required to make a deletion. o “Delete” = Record Mode “D”. Send the information required to numerically “cancel” a deleted record : o “Reverse” = Record Mode = “R”.

If the record mode is not determined by the data source, you have to specify which record mode is being sent. A corresponding field has to be added to the extract structure. The field must be named in the data source. E.g : “R” in a “Cancel” data source field, assigned to the ‘0RECORDMODE’ InfoObject of the InfoSource, indicates that the record is deleted from the ODS. Extractors cannot send all the different types of image. The output images that are available, depend on the functions of the individual extractor. No single extractor offers all the different types of image. Technical InfoObjects 0RECORDMODE (data element RODMUPDMOD) Delta Methods are predefined in the RODELTAM system table. The most important delta methods are : ABR Delta with After Image, Before Image and Reverse Image, that in push mode, are pushed into the delta queue and serialized according to data package. AIM

Delta with only After-Images that are pushed in push mode into the delta queue.

ADD Additive delta using extractor (serialised according to request). NEWE/D

New, unique data records are generated.

AIMD

Like AIM, but with additional delete Ids

CUBE Additive delta using extractor (e.g. used by export data source of an InfoCube; no serialization required) ODS Delta with After-Image, Before-Image, and Reverse-Image using extractor (used by the export data source of an ODS). Dimensions of Data Extraction Extraction Mode : The extraction mode refers to the range of data extracted from the source system. Basically two modes : Full extraction and Delta Extraction. Extraction Scenario : Data can either be pushed into (publish and subscribe, initiator : OS) or pulled from (request and respond, initiator : BW) an operational system Data latency. Refers to timeliness of data extraction. i.e whether it is Synchronous (Real time), asynchronous (stored and forwarded), or asynchronous batch (on-demand or eventdriven or scheduled). Extraction Scope. Refers to the specifications of how data must be extracted from a projection (which fields), a selection (which records), and an aggregation (at what level of granularity) perspective. Every extract structure can be viewed along these four dimensions. Planning with SAP SEM and SAP APO or customer analytics with SAP CRM that require delta extractions, push scenarios and close-to-real-time updates in the data warehouse. The main problem in implementing delta extraction lies in identifying the deltas. There are two basic approaches to delta loading: The use of delta queues and the use of timestamps. Physical updates : Data is updated in SAP R/3 in two different ways: synchronously and asynchronously. Asynchronous : V1 or V2 updates. V1 denotes time critical updates used for updateing the actual transaction tables. V2 denotes non-time-critical updates used for updating statistics tables related to the transaction tables.