Standardization is a key aspect of SAP BW Layered, Scalable Architecture (LSA), SAP’s best practice in Enterprise Data Warehousing. One of the ways to realize standardization in the data staging process is developing generic, reusable ABAP building blocks with a comprehensive interface.

In every data flow we have to deal with the first inbound mapping of DataSource fields to InfoObjects within the transformation. Therefore, it makes sense to identify this process as a modeling pattern and use such a building block to facilitate the process. Let’s call it Mapping Services.

This document describes how the ABAP Objects classes for Mapping Services were developed, including all necessary ABAP Workbench objects.

Please refer to my blog Mapping Services – Inbound Mapping of DataSource Fields to InfoObjects for a conceptual overview and more information on maintaining the mapping control table and calling Mapping Services in the context of the transformation.

Please have a look here to download the attachments.

Mapping Services Class

The class YCL_BW_MAPPING is a reusable building block and facilitates the mapping from DataSource fields to InfoObjects during the first inbound transformation, i.e. in the Data Acquisition Layer the transformation from DataSource to Outbound InfoSource. This chapter describes how the class is developed.

Use the Class Builder to create the class YCL_BW_MAPPING. Go here via t/code SE24 or SAP menu path:

Tools > ABAP Workbench > Development > Class Builder

Source Code of the Implementing Class

Please refer to the attached text document for the source code of the class YCL_BW_MAPPING.

You can easily copy and paste the source code in the Class Builder. Switch from the “Form-Based” to the “Source Code-Based” maintenance.

Overview of the Attributes

The following attributes are defined:

• P_DATASOURCE – DataSource (OSOA/OSOD);
• P_R_EXCEPTIONS – BW Mapping Exception Class;
• P_R_REQUEST – Interface Between IPRO Admin Tab and Request;
• P_SOURCEOBJECT – Source Object for a DTP;
• P_SOURCESYSTEM – Source System for DataSource;
• P_SOURCETYPE – Type of Source Object for a DTP;
• P_TH_MAPPING – Mapping Table.

Overview of the Methods

The following methods are implemented:

• EXECUTE – Execute Mapping Services (Expert Routine);
• CHECK_MAPPING – Check if Mapping can be Executed;
• GET_SOURCEOBJECT – Determine Source Object (DataSource);
• MAIN_PROCEDURE – Main Procedure to Execute Mapping;
• READ_BW_CONTROL_FROM_DB – Read BW Control Table from Database.

Exception Class

The class YCX_BW_MAPPING is created to facilitate exception handling using the “class-based exception” concept. Most of the implementation is carried out automatically. Below you can find an overview of all necessary additions to the generated proposal.

Use the Class Builder to create the exception class YCX_BW_MAPPING. Go here via t/code SE24 or SAP menu path:

Tools > ABAP Workbench > Development > Class Builder

Please note to create the exception class with the option “with message class”.

 

Figure 1: Create Exception Class – Initial Screen

Properties

The Properties should look as follows. Make sure that message class YBWMAP is specified.

 

Figure 2: Exception Class – Properties

Interfaces

The Interfaces should look as follows. Make sure that IF_T100_MESSAGE is present since it’s crucialfor maintaining the T100 messages. If it’s missing, you can add it manually.

 

Figure 3: Exception Class – Interfaces

Attributes

Please find below an overview of all attributes which have to be added manually. The automatically generated attributes are not described.

 

Attribute	Level	Visibility	Read only	Typing	Associated type	Description
DATASOURCE	Instance Attribute	Public	Yes	Type	ROOSOURCER	DataSource (OSOA/OSOD)
DSFIELDNAME	Instance Attribute	Public	Yes	Type	RSFIELDNM	DataSource Field name
SOURCESYSTEM	Instance Attribute	Public	Yes	Type	RSDLOGSYS	Source System for DataSource
TGTFIELDNAME	Instance Attribute	Public	Yes	Type	RSFIELDNM	Target Field name

Table 1: Attributes

Texts

Please find below an overview of the custom defined exception texts. As you might have noticed, every message is connected to a corresponding T100 message.

 

Exception ID	Text	T100 Message	Attributes
TARGET_FIELD_MISSING	Target field name &TGTFIELDNAME& is missing in result package	YBWMAP 003	TGTFIELDNAME
DATASOURCE_FIELD_MISSING	DataSource field name &DSFIELDNAME& is missing in BW control table	YBWMAP 002	DSFIELDNAME
MAPPING_TABLE_NO_RECORDS	No suitable records for DataSource &DATASOURCE& &SOURCESYSTEM& in BW control table	YBWMAP 001	DATASOURCE SOURCESYSTEM
SOURCE_OBJECT_FAILED	Source object determination failed	YBWMAP 000

Table 2: Exception Texts

Methods

Next to the automatically generated methods, one additional method has to be created: CREATE_LOG_REC. This method is used to create a record for log object in the context of the expert routine. Please refer to the attached text document for the source code of method CREATE_LOG_REC.

Other ABAP Workbench Objects

In this chapter, the remaining ABAP workbench objects are discussed. The following objects have to be developed:

• T100 messages;
• Search Helps;
• BW control table.

T100 Messages

A new message class YBWMAP (Mapping Services) has to be created. This message class contains the various messages used in exception class YCX_BW_MAPPING.

To create the message class YBWMAP, use t/code SE91 or SAP menu path:

Tools > ABAP Workbench > Development > Programming Environment > Messages

 

Message	Message Short Text	Self-expl.
000	Source object determination failed	Yes
001	No suitable records for DataSource &1 &2 in BW control table	Yes
002	DataSource field name &1 is missing in BW control table	Yes
003	Target field name &1 is missing in result package	Yes

Table 3: Message Class

Search Helps

Two search helps have to be created:

• YBW_DSFIELD: Search Help for DataSource Fields;
• YBW_IOBJFNM: Search Help InfoObject and Field Name.

 

To create the search helps, use t/code SE11 or SAP menu path:

Tools > ABAP Workbench > Development >ABAP Dictionary

 

Figure 4: Search Help for DataSource Fields

 

Figure 5: Search Help InfoObject and Field Name

BW Control Table

BW Control Table YBWMAPPING has to be created. The table should be created as “customizing table” and “table maintenance” enabled. A table maintenance dialog can be generated for this table but is not described any further.

To create the table, use t/code SE11 or SAP menu path:

Tools > ABAP Workbench > Development >ABAP Dictionary

The delivery and maintenance settings of the BW Control Table are as follows.

 

Figure 6: BW Control Table – Delivery and Maintenance Settings

 

Table YBWMAPPING is used by the class YCL_BW_MAPPING. This table stores the mapping rules. The configuration of the table looks as follows.

 

Figure 7: BW Control Table – Fields

 

Figure 8: BW Control Table – Entry Help/Check

 

The following foreign key relationships have to be maintained.

 

Figure 9: BW Control Table – Foreign Key (1)

 

Figure 10: BW Control Table – Foreign Key (2)

 

Figure 11: BW Control Table – Foreign Key (3)