Generic Extraction business Requirement, through function module,

Question

Generic Extraction business Requirement, specifically through function module and source code in function module.

Answer 1

Dear Karthik,
Go to transaction SBIW -> Generic Datasource -> Maintain Generic Datasources -> Choose Master/Transaction Data -> Maintain proper entries (Application Component, Descriptions) -> Extraction by FM if you want to extract using FM.
Maintaining Generic DataSources - Independently of application, you can create and maintain generic DataSources for transaction data, master data attributes or texts from any kinds of transparent tables, database views, InfoSets of the SAP query or using a function module. As a result, you can make use of the generic extraction of data.
Creating a Generic DataSource
       1.      Select the DataSource type and give it a technical name.
       2.      Choose Create. The creating a generic DataSource screen appears.
       3.      Choose an application component to which the DataSource is to be assigned.
       4.      Enter the descriptive texts. You can choose any text.
       5.      Choose from which datasets the generic DataSource is to be filled.
                            a.      Choose Extraction from View, if you want to extract data from a transparent table or a database view. Enter the name of the table or the database view.
After generation, you get a DataSource whose extract structure is congruent with the database view or the transparent table view.
For more information about creating and maintaining database views and tables, see the ABAP Dictionary Documentation.
                            b.      Choose Extraction from Query, if you want to use a SAP query InfoSet as the data source. Select the required InfoSet from the InfoSet catalog.
After generation, you now have a DataSource whose extract structure matches the InfoSet.
For more information about maintaining the InfoSet, see the System Administration documentation.
                            c.      Choose Extraction using FM, if you want to extract data using a function module. Enter the function module and extract structure.
The data must be transferred by the function module in an interface table E_T_DATA.
For information about the function library, see the ABAP Workbench: Tools documentation.
                            d.      With texts, you also have the option of extraction from domain fixed values.
Maintain the settings for delta transfer where appropriate.
       7.      Choose Save.
Note when extracting from a transparent table or view:
If the extract structure contains a key figure field, that references to a unit of measure or currency unit field, this unit field must appear in the same extract structure as the key figure field.
A screen appears in which you can edit the fields of the extract structure.
       8.      Editing the DataSource:
       Selection
When scheduling a data  request in the BW Scheduler, you can enter the selection criteria for the data transfer. For example, you may want to determine that data requests are only to apply to data from the previous month.
If you set the Selection indicator for a field within the extract structure, the data for this field is transferred in correspondence with the selection criteria in the scheduler.
       Hide field
You should set this indicator to exclude an extract structure field from the data transfer. As a result of your action, the field is no longer made available in BW when setting the transfer rules and generating the transfer structure.
       Inversion
Reverse postings are possible for customer-defined key figures. For this reason, inversion is only possible for certain transaction data DataSources. These include DataSources that have a field that is indicated as an inversion field, for example, the field update mode in the DataSource 0FI_AP_3. If this field has a value, then the data records are interpreted as reverse records in BW.
Set the Inversion indicator if you want to carry out a reverse posting for a customer-defined field (key figure). The value of the key figure is then transferred in inverted form (multiplied by –1) into BW.
       Field only known in exit
You can enhance data by extending the extract structure for a DataSource using fields in append structures.
The indicator Field only known in Exit is set for fields of an append structure. In other words, by default these fields are not passed onto the extractor from the field list and selection table.
Deselect the indicator Field Only Known in Exit to enable the Service API to pass on the append structure field to the extractor together with the fields of the delivered extract structures in the field list as well as in the selection table.
9. Choose DataSource -> Generate.
The DataSource is now saved in the source system.
Maintaining Generic DataSources
·        Change the DataSource
To change a generic DataSource, in the initial screen of DataSource maintenance, enter the name of the DataSource and choose Change.
You can change the assignment of a DataSource to an application component as well as the texts of a DataSource. Double-clicking on the name of the table, view, InfoSet or extract structure takes you to the appropriate maintenance screen. Here you can make changes required to add new fields. You can fully swap transparent tables and database views, but not InfoSets. If you return to the DataSource maintenance and choose Create, the screen for editing a DataSource appears. To save the DataSource in the SAP source system, choose DataSource  -> Generate.
If you want to test extraction in the source system independently of a BW system, choose DataSource  ->  Test Extraction.
·        Delta DataSource
In the Change Generic DataSource screen, you can delete any DataSources that are no longer relevant. If you are extracting data from an InfoSet, delete the associated query. If you want to delete a DataSource, this must not be connected to a BW system.
Also visit :[Data Extraction from SAP Source System | http://help.sap.com/saphelp_nw04/helpdata/en/28/4c553c42360a40e10000000a114084/content.htm]
Regards,
Naveen.