Quelltext der Seite Delta Process with ODP (SAP BW/4HANA)

== The Delta Process ==

The different delta processes are specified in table <code>RODELTAM</code>

The delta process is based on the following mechanisms:

{| class="wikitable"
! Mechanism !! Description
|-
| DTP Extraction Mode || Full or delta
|-
| Delta Mechanism || 
* Delta queue managed by application
* Delta queue managed by extractor based on delta field
* Delta determined by target BW/4HANA based on delta field
|}

DataSource properties that affect the overall delta process:

{| class="wikitable"
! Mechanism !! Description
|-
| Delta Type || How do records enter the operational delta queue?
|-
| Serialization || Data retrieved in original sequence?
|-
| Record Modes || What kind of records are in the operational delta queue?
|}

=== Serialization ===

Specified in <code>RODELTAM-DREQSER</code>

Serialization is necessary, when updating a ADSO with the Overwrite Rule Type on key figures.

Possible values for serialization:

* No serialization
* Serialization required between requests
* Serialization required at data package level

=== Delta Type ===

Specified in <code>RODELTAM-DREQSER</code>

{| class="wikitable"
! Value !! Description
|-
| ' ' || No delta type defined
|-
| A || The DataSource determiney the delta with Application Link Enabling update pointers. Can be used for generic DataSources to provide delta figures.
|-
| D* || The SAP application writes delta records (PUSH) directly to the operational delta queue (ODQ)
|-
| E* || The DataSource determines the delta through the extractor on request (PULL) and places them in the ODQ. Used in applications in which delta can be determined through i.e. timestamp, date.
|-
| F || Delta records are loaded by flat file
|-
| X || Obsolete
|}
(*) = most frequent use cases

=== Record Modes ===

Records in the source system can be created, changed and deleted.

ADSO types have impact on how delta images are processed. Therefore modeling ADSOs depends on the delta images provided by the DataSource.

{| class="wikitable"
! ADSO Modelling Properties !! Key Figure Transformations
|-
| Standard DataStore Object || Overwrite or Summation
|-
| Staging DataStore Object || Overwrite or Summation
|-
| DataMart DataStore Object || Summation
|}

Characteristic Values for Record Modes:

{| class="wikitable"
! Record Mode !! Provided Image Type !! Description !! Zweck
|-
| ' ' || after-image || The record provides an after-image of the change.

State of a record after it has been changed or added. Can only be used with Data Mart ADSO if corresponding before-image is in the request.
|-
| X || before-image || The record provides a before-image of the change.

State of a record before it has been changed or deleted. All key figures must be transferred with a reversed sign (plus/minus). Responsible for reversing the sign is either the extractor or the SAPI. These records are ignored when loading to a Standard or Staging ADSO with activation option ''Overwrite''. The before-image complements the after-image
|-
| A || additive-image || The record provides an additive-image (difference) of the change.

For attributes that can be aggregated, only the changes are transferred. If attributes cannot be aggregated, the status after data was changed or created is transferred. Record can be updated to Data Mart ADSO without restrictions, but requires an additive update to be made to Standard or Staging ADSO with Activation option.
|-
| D || delete || The record must be deleted.

Only the key is transferred. Can only be updated to an Standard or Staging ADSO with Activation option.
|-
| R || reverse-image || The record provides a reverse-image of the change.

The content is equivalent to a before-image. The only difference occurs when updating an Standard or Staging ADSO with Activation option. In this case an existing record with the same key is deleted.
|-
| N || new-image || The record provides a new-image.

The content of this record is equivalent to an after-image without a before-image. A new-image should be transferred instead of an after-image when a record is created. The new-image complements the reverse-image.
|}

Description of relationships between record mode and the correct update of data targets for transaction data:


{| class="wikitable"
! Use Case !! Image Type !! Record Mode !! Possible ADSO-Types and Update Methods
|-
| New (create) or New Status
| After image 
| ' ' 
| 
* Standard / Staging DSO (with activation) &rarr; Move (Overwrite)
|-
| Difference
| Additive image 
| A 
| 
* Data Mart ADSO &rarr; Sum
* Standard / Staging DSO (with activation) &rarr; Sum only
|-
| Reversal and new status
| Before + After image 
| X + ' '
| 
* Data Mart DSO &rarr; Sum
* Standard / Staging DSO (with activation) &rarr; Sum / Move (Overwrite)
|-
| Create or Reversal
| New or Reverse image 
| N or R 
|
* Data Mart DSO &rarr; Sum
* Standard / Staging DSO (with activation) &rarr; Sum / Move (Overwrite)
|-
| Delete
| Delete image 
| D
| 
* Standard DSO (processed during activation) &rarr; Move (Overwrite)
|}

Detailed informations about what is sent by the DataSource during the delta process:

https://wiki.scn.sap.com/wiki/display/EIM/Dataflows+for+each+Extractor+Delta+Process+Type

[[Kategorie:SAP]]