BAPI开发资料介绍

nullnullBAPI Development TechEd Hamburg, April 2000 Anton Deimel Internet Business Framework Architecture SAP AGBAPI DevelopmentBAPI DevelopmentIntroduction BAPI DevelopmentChange ManagementCustomer EnhancementsThe SAP Business FrameworkThe SAP Business FrameworkAn integrated family of distributed products The distributed products are made up of cooperating components Strategic product architecture Integration scenarios (example: HR Master Data Distribution) Business components (example: Human Resources) Business object types (examples: Employee, Applicant, ...) BAPI interfaces (example: Employee.ChangeAddress) ALE enables cross-component integrationBusiness Objects as a Wrapper LayerBusiness Objects as a Wrapper LayerAim of the “Wrapper” approach: - Object-based view and OO access to data and processes in the R/3 System - However, implementation is mainly still functionalWhat Is a BAPI?What Is a BAPI?Business Application Programming InterfaceA BAPI is a well-defined interface to the processes and data in a business application system, defined as a method of a business object in the BOR. A BAPI is implemented as a function module.How Is a BAPI Implemented in the R/3 System?How Is a BAPI Implemented in the R/3 System?Function Library (SE37)Defined in the BORImplemented as a function modulefunction bapi_salesorder_getlist. ------------------------------------------------------------ Local interface: Importing VALUE(CUSTOMERNUMBER) LIKE ... ... Exporting VALUE(RETURN) LIKE ... Tables SALESORDERS STRUCTURE ... ------------------------------------------------------------ perform ...SalesOrder.GetListParameters: CustomerNumber Imp ... Return Exp SalesOrders Imp/ExpBORImplemented by:BAPI DevelopmentBAPI DevelopmentIntroduction BAPI DevelopmentChange ManagementCustomer EnhancementsBAPI Development - Getting StartedBAPI Development - Getting StartedBAPI Workshop (optional) Use the BAPI Explorer (as of 4.6A) BAPI Project (in the BAPI Explorer) Programming guideline for BAPIs Completely revised for 4.6C Made more concise (approx. 25 pages) Detail information in appendix All information is available As Ken documentation (CA-BFA) In SAPNet at the BFA homepage (alias IBF) Steps for Developing a New BAPISteps for Developing a New BAPIIntegrated in the BAPI Explorer (as of 4.6A)BAPI Development Process: AnalysisBAPI Development Process: AnalysisAn (integration) scenario defines the business process to be implemented either between various R/3 components or between R/3 components and non-SAP components. An integration scenario forms the basis for developing BAPIs! Analysis - Draw Up a ScenarioAnalysis - Draw Up a ScenarioIntegration scenario Issues Which requirements are met? What does the business process look like? How will the business process be realized in the IT-system? (In other words, describe the scenario) Which business object types are involved? Is there already an object model? Which methods (BAPIs) are required? Analysis - Business Object TypesAnalysis - Business Object TypesBusiness object types Issues Object model Independence, uniqueness Generally applicable for use in BAPIs, Workflow, ArchivLink Performance, maintenance, ... Responsibility for object Names and conventions are important BAPI Development Process - Designing BAPIsBAPI Development Process - Designing BAPIsBAPIs BAPI signature defined at conceptual level Issues Standardized BAPIs Full, complete scenario Complexity of interfaces Performance, maintenance, ... Precise names are importantConventions in the Design PhaseConventions in the Design PhaseConventions for BAPI methods Specify whether it is an instance method or class method Method name must be in English BAPI has a return parameter Customer enhancement possible (ExtensionIn, ExtensionOut) Conventions for parameters Parameters and field names must be in English ISO code fields for ISO-relevant fields All quantity fields must also have corresponding quantity unit fields All currency amounts must also have corresponding fields for currency descriptions/namesBAPI Development Process - ImplementationBAPI Development Process - ImplementationCreate structures for BAPI function module parameters in ABAP Dictionary Create BAPI function module Include BAPI function module in BOR as API method of the corresponding business object BAPI documentation BAPI-ALE integration  Create Structures in DDIC - Data Formats BAPIs are programming interfaces! Values are not formatted No domain conversion Exception: external keys Example: WBS element The format for date fields is YYYYMMDD ISO code (countries, language, currency, quantities) Additional field for ISO values Currency amounts have four places after the decimal point Pass on with correct number of places Domains BAPICURR, BAPICUREXT Create Structures in DDIC - Data Formats  Create Structures in DDIC (2)  Create Structures in DDIC (2) Every parameter has a DDIC data structure Name of structures: BAPI* 30 characters (before 4.0, 10 characters) No INCLUDEs or APPENDs Maintenance of check tables, search help for BAPI F4 “Frozen” when BAPI is released BAPI structures must have English field names Report BBAPIFLD generates proposed values for each BAPI structure Define English default names for data elements Example: COMP_CODE for the data element BUKRS  Create BAPI Function Module (1) Create BAPI Function Module (1)Naming convention: BAPI__ One function group for all the BAPIs of a business object (recommended).  Create BAPI Function Module - Define Interface Create BAPI Function Module - Define InterfaceTake key fields into account Instance method: all key fields are mandatory importing parameters Class method: no key fields as parameters Create-method: all key fields are exporting parameters Use only full key (no partial key allowed) Every key field is represented by a scalar parameter in the function module The key parameter in the function module has the same name as the key field in the BOR Use standard data structures for Return, ExtensionIn and ExtensionOut The function module must be RFC-enabled Create BAPI Function Module - Implement the Function Module (1) Create BAPI Function Module - Implement the Function Module (1)Database changes always by using update task BAPI can not have any screen output Intercepting of all messages A BAPI does not cause a program termination (“A” message) A BAPI may not dispatch a COMMIT-WORK command Transaction Model - Explicit COMMITTransaction Model - Explicit COMMITLogonLogoffBAPI1BAPI2ClientR/3TimeRFC sessionSAP LUWBAPI: TransactionCommitCOMMIT WORK Create BAPI Function Module - Implement Function Module (2) Create BAPI Function Module - Implement Function Module (2)No Exceptions Error via return parameter (structure or table) Parameter name RETURN DDIC structure BAPIRETURN1, BAPIRET2 (as of 4.0) Optional: Application Log Logging of errors Classification of errors Optional: More error tables In addition to the return parameters, you can also define application-specific error tablesError handling Create BAPI Function Module - Implement Function Module (3) Create BAPI Function Module - Implement Function Module (3)Provide customer exits for customer enhancements Mapping BAPI structure - internal structure Transaction ”BDBS” generates function modules that do the mapping between internal and external structures. (BAPISAP and SAPBAPI) ABAP source code for the MOVE between German and English field names ISO code conversions Converting currency amounts Converting internal/external keys Create BAPI Function Module - Generic BAPI Services Create BAPI Function Module - Generic BAPI ServicesError messages: Function module BALW_BAPIRETURN_GET1 writes data to BAPIRETURN1 Currency amounts Domains BAPICURR (19+4) and BAPICUREXT (19+9) BAPI_CURRENCY_CONV_TO_EXTERNAL BAPI_CURRENCY_CONV_TO_INTERNAL Naming conventions for field with ISO codes _ISO Include as API Method of Corresponding BO Include as API Method of Corresponding BOIn the Business Object Builder: Select object type to be changed UtilitiesAPI methodsAdd method BAPI Wizard Specify function module BAPI__ Name of method: Words begin with capital letters; do not use any underscores Parameters: adapt names (capital letters) Have the system generate method source code for workflow automatically Document the BAPI Document the BAPIDocument all parameters fully Documentation on return parameter contains all relevant error messages Documentation specifies whether a COMMIT-WORK was used Note: Documentation guidelines available in BAPI Programming Guideline BAPI-ALE Integration BAPI-ALE IntegrationBAPI has two working modes synchronous as RFC asynchronous by sending an IDoc Guideline as of 4.0: All (new) asynchronous interfaces (IDocs) are based on BAPIs How do you get an IDoc? Develop the required BAPIs Generate the ALE-Interface (use transaction BDBG): Message type, Idoc type Two ALE function modules for inbound and outbound In this way IDoc interface is identical to BAPI interface BAPI Development Process - ReleaseBAPI Development Process - Release What is released? Function module released externally (in Function Builder) Business object type released (in BOR) Method released in BOR If applicable, corresponding IDoc released (for asynchronous communication) Once released, the interface may only be changed in a way that is compatible Check by DDICSidetrack: Enhancements for BAPIsSidetrack: Enhancements for BAPIsCustomers In the BAPI, the ExtensionIn and ExtensionOut parameters are made available The parameters are used as data containers in which the customer-specific parameters can be transferred Structuring by means of table extensions Code in customer exits See: Customer Enhancement Guide Partners and IBUs/Add-On Define a subtype of the business object Insert new method Generic BAPI Services (1)Generic BAPI Services (1)BapiService object “BAPIs are programming interfaces”, internal data presentation DataConversionExt2Int() DataConversionInt2Ext() BAPI documentation (F1) FieldhelpGetDocu() InterfaceGetDocu() Message handling MessageGetDetail() Programming model, logical unit of work TransactionCommit() TransactionRollback()BapiServiceGeneric BAPI Services (2)Generic BAPI Services (2)HelpvaluesHelpvalues object (F4) BAPI GetList() Determines possible entries for a field in a BAPI call Input: business object, BAPI, parameters, field, search help Output: list of possible values for the field in question BAPI GetSearchhelp Determines existing search help services Input: business object, BAPI, parameters, field Output: List of search help services These search help services can then be used in the GetList BAPIBAPI DevelopmentBAPI DevelopmentIntroduction BAPI DevelopmentChange ManagementCustomer EnhancementsChange ManagementChange ManagementCustomers and partners use the BOR for Workflows of their own Access to external programs via BAPIs ... Incompatible changes will result in terminations in these programs Incompatible changes must be avoided!What Does “Incompatible” Mean? (BAPI example)What Does “Incompatible” Mean? (BAPI example)Different syntax Transaction is no longer technically possible (import/export) Different semantic Fields of the same type/length, but with a new meaning Different functionality Does the BAPI execute the same functionality? If you have the same input, does you also get the same output as before? If the BAPI makes changes to the database: are these changes coherent with the changes of the previous version?BAPIs - Compatible and Incompatible Changes BAPIs - Compatible and Incompatible Changes Compatible changes New optional parameters (fields, structures, tables) Add on new optional fields to existing parameters Incompatible changes New mandatory parameters (fields, structures, tables) Functional dependencies between new and old parameters Semantic changes to parameters Deleting, renaming, changing the length of, changing the data type of parameters Defined process ("End of Life”) (see next slide) “End of Life” Process (BO and BAPIs)“End of Life” Process (BO and BAPIs)What happens in the case of incompatible changes? Example: 3.1 Object OLD is replaced in Release 4.0 by Object NEW 4.0 Change release 4.5 Subsequent releaseBAPI DevelopmentBAPI DevelopmentIntroduction BAPI DevelopmentChange ManagementCustomer EnhancementsEnhancements to Business Objects and BAPIsEnhancements to Business Objects and BAPIsBAPI customer enhancement concept Enhancement option for BAPIs predefined by SAP For customers only (not for partners or Add-Ons) Other change concepts for BAPIs New customer-specific business objects Changes to existing SAP business objectsnullStandard concept proposed by SAP Principle: BAPI enhancement option predefined by SAP The BAPI must be intended by SAP for enhancement Benefits: Not a modification Largely generic concept Easy to implement In simple cases even without own coding Customer Enhancement Concept Elements of a Customer EnhancementElements of a Customer EnhancementExtensionIn and ExtensionOut parameters in the BAPI interface Used as containers for customer-specific data BAPI table extensions (data types) Enable simple (syntactic) interpretation of the data transferred Customer exits in the BAPI function module Enables a jump to customer-specific subroutines ExtensionIn and ExtensionOut ParametersExtensionIn and ExtensionOut ParametersContainers for import and export of customer-specific data without modification of the interface Table parameters Data type of the parameters is a standard Dictionary structure:BAPI Table ExtensionsBAPI Table ExtensionsInterpretation of data in container A structure in the ABAP Dictionary (= data type) must be specified for each data record. This information determines how the data are to be interpreted. Stored in the STRUCTURE field of BAPIPAREX Provides simple support for importing and exporting data Particularly powerful with table enhancement Define a BAPI Table Extension (= structure) for every DB table to be enhanced Customer defines additional fields in a structure of his own, and includes these both in the DB table (table enhancement) and in the BAPI Table Extension structure Supports consistency and generic data processing BAPI Table Extensions (2)BAPI Table Extensions (2)BAPI Table Extension (Structure)Database TableCustomer Enhancement Structure Customer ExitsCustomer ExitsA customer exit is a point in the source code provided by SAP from which it is possible to go to additional customer code A BAPI function module usually contains 2 customer exits First exit: For checking the customer data in ExtensionIn Second exit: For processing customer data If applicable, update database Write data to ExtensionOut nullDefine BO in BOR (in customer name range) Also possible to create methods (BAPIs), attributes and events If you define a new BAPI: create the function module and store meta information in BOR Support provided by BAPI development tools (BAPI Explorer) Support provided by guides Customer-Specific Business ObjectsChanging Existing Business ObjectsChanging Existing Business ObjectsPossible changes: New methods (BAPIs), attributes, events Change existing BAPIs Define a subtype for the SAP business object Make all changes to the subtype only! This means that, technically, changes do not represent modifications Semantic comparison necessary for release change Buzzword: Fragile Base Class Problem It is more a case of delegation than inheritance Inheritance utility used to ensure interface compatibility However, polymorphism is not supported directly Changing Existing Business Objects (Details)Changing Existing Business Objects (Details)Define new methods (BAPIs), attributes, events for the subtype Proceed in the same way as for customer-specific business objectsDelegation from Supertype to SubtypeDelegation from Supertype to SubtypeIn the BOR, you can specify that all calls to the supertypes are automatically delegated to the subtypes This means that BOR applications defined by SAP (Workflow, for example) also flow via the customer object Note, though, that this applies only for BOR applications But, generally speaking, not for calls from external platforms If customer applications are integrated, we recommend that you always use the subtypeStrategies for Redefining BAPIs (1)Strategies for Redefining BAPIs (1)Create a new implementing function module Use the original functionality by calling up This procedure is recommended because it results in clean-cut encapsulation of the original BAPI Strategies for Redefining BAPIs (2)Strategies for Redefining BAPIs (2)Compatible modification of superordinate function module Advantage: Better coupling between original code and enhancement Disadvantages: Encapsulation no longer exists Modification of SAP code Strategies for Redefining BAPIs (3)Strategies for Redefining BAPIs (3)Create a new function module by copying Advantage: More flexibility Disadvantages: Further data (global variants) might also have to be copied Much effort involved in making changes for a release upgrade Difficult to maintain Generally not recommendedThe SAP Business Framework - OutlookThe SAP Business Framework - OutlookAn integrated family of distributed intra and inter enterprise products Integration via XML All BAPIs, IDOCs and relevant RFCs are supported by an new Interface Repository Strategic product architecture Integration scenarios Business components Business object types XML BAPI interfaces Business componentBOBOBAPIBOBAPIBusiness ComponentBAPISAP Internet Business FrameworkXML based Application Linking