how to model a gateway service based on cds view for abap using sadl

7/17/2019 How to Model a Gateway Service Based on CDS View for ABAP Using SADL

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SAP NetWeaver

How-To Guide

How To Model a Gateway Service based onCDS View for ABAP using SADL

Applicable Releases:

SAP NetWeaver AS ABAP 7.4 SP5

Target Audience:

ABAP Developers

Version 1.0

February 2014



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Document History

Document Version Description

1.00 First official release of this guide



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Table of Contents

1. Scenario ................................................................................................................................ 1

2. Background Information ..................................................................................................... 1

2.1

Service Adaptation Definition Language (SADL) and Business Entities ...................... 1

2.2 Core Data Services (CDS) for ABAP............................................................................ 1

2.3 Data Model ................................................................................................................... 2

3. Prerequisites ........................................................................................................................ 2

4.

Step-by-Step Procedure ...................................................................................................... 3

4.1

Open SAPGUI within ADT ............................................................................................ 3

4.2

Create Gateway Project ............................................................................................... 3

4.3 Create Entity Type ........................................................................................................ 4

4.4 Create Entity Set........................................................................................................... 6

4.5

Service Implementation ................................................................................................ 7

4.6

Generate Runtime Objects ......................................................................................... 10

4.7 Service Registration ................................................................................................... 12

4.8 Testing Gateway Service ............................................................................................ 14

5. Appendix ............................................................................................................................ 18

5.1 Appendix A – Abbreviations ....................................................................................... 18

5.2 Appendix B – References ........................................................................................... 18

5.3 Appendix C – Link to ABAP for SAP HANA Reference Scenarios ............................ 18

5.4

Appendix D- Links to SAP NetWeaver Gateway Documents .................................... 19



How To Model a Gateway Service based on CDS View for ABAP using SADL

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1. ScenarioThis guide will help you to create read-only OData Service, using SAP NetWeaver Gateway, whichconsumes Core Data Services (CDS) view as its data model. This guide shows a model-based

approach of creating the service. The model-based approach substantially reduces the manual effortsand thereby reducing the Total Cost of Development (TCD). This guide will assist you to:

Create a OData Service using SAP NetWeaver Gateway

Consume Core Data Services (CDS) view as data model

Generate code for Read (GetEntity), Query (GetEntities) for an Entity Set thereby avoidingmanual effort of writing the code.

2. Background Information

2.1 Service Adaptation Definition Language (SADL) andBusiness Entities

Service Adaptation Definition Language (SADL) is a framework, which enables consumption ofdifferent business object models, and other entity-based models, in particular DDIC tables and views,in a uniform way. Knowledge of the details of the modeling frameworks, such as Business ObjectProcess Framework (BOPF) or Business Object Layer (BOL) is not required. The SADL entity modelexposes all the required information to the gateway service. In Gateway, SADL entities are known asBusiness Entities.

With SADL, it is possible to push down queries directly to the database, thereby improving responsecycle times. With SADL, very large amounts of data (millions of records) can be retrieved anddisplayed quickly.

Using SADL framework, the Gateway transaction (T-Code) SEGW assists you to create an ODataService without writing the code for Read (GetEntity), Query (GetEntitySet), Create, Delete, andUpdate. As a Gateway developer, you need not understand the internals of SADL framework asGateway takes care of everything.

2.2 Core Data Services (CDS) for ABAPCore Data Services (CDS) enhance SQL to allow defining and consuming semantically rich datamodels, thereby improving consumption, performance and interoperability. CDS simplifies andharmonizes the way you define and consume your data models, regardless of the consumptiontechnology. CDS in ABAP provides you with a data definition language (DDL) for defining semanticallyrich database tables/views (CDS entities) and user-defined types in the database.

For several years for now, it is possible to define views in the ABAP Dictionary, but these views arequite restricted. For example, you can only define inner join for database views. Outer joins areavailable only for help and maintenance views. However, it is not possible to perform aggregations inviews or define nested views. With ABAP 7.4 SP05, a new editor is available to define views directly inthe Eclipse-based ABAP development environment. With this Source-based editor you can defineCDS entities, which can be consumed in ABAP programs using Open SQL.

The CDS View building provides another way of code pushdown using features that are similar as inOpen SQL. With CDS View building it is possible to define

1. Projections, aggregations, and groupings

2. Use expressions (like CASE), SQL built-in functions

3. UNION and UNION ALL and non-equi INNER JOINs

Nesting of Views with associations between the View entities (associations can be consumed in theWHERE clause as well as in expression in Open SQL queries)




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2.3 Data ModelBefore getting started, you must generate data related to Enterprise Procurement Model (EPM). Youcan use the transaction SEPM_DG_OIA to generate the data for EPM model. For more informationabout EPM, see http://scn.sap.com/docs/DOC-31458

For creating OData service, use the CDS view SEPM_CDS_OPEN_INVOICE_REDUCED. The ABAPview name of this CDS view is SEPMAPPS _CDS_OIR . This CDS view is part of the packageS_EPM_OIA_APPS_PROVIDER . This CDS view fetches all the Open Sales Orders – sales orderswhose payment is yet to be made by the Buyers. Buyer Name, Dunning Level, Overdue Invoice

Amount, Currency are some of the details retrieved for each of the Sales Order. Each Sales Order canhave one or more Sales Order Items and the invoice amount can be in different currencies. For agiven Sales Order ID the data is grouped by Currency and the aggregated invoice amount isdisplayed.

3. Prerequisites

1. Knowledge of creating OData Service using SAP NetWeaver Gateway2. SAP NetWeaver Gateway is configured and customized in SPRO transaction. Gateway must be

activated, System Aliases must be set with at least one entry for LOCAL system, RemoteFunction Call (RFC) destination for local Gateway registration is configured and requiredGateway Settings are set

3. SICF service /default_host/sap/opu is activated

4. SAP NetWeaver (NW) version 7.4 SP5 or higher is installed

5. Knowledge of working with ABAP Development Tools (ADT)

6. Knowledge of NW Reference Scenario, Enterprise Procurement Model (EPM) will be useful

7. Knowledge of ABAP Core Data Services (CDS) and CDS View Building will be useful

8. Use ADT to connect to the ABAP system and thereby create ABAP project in the Project

Explorer [ABAP Perspective]. Refer to this link to follow step- by- stepprocesshttp://www.sdn.sap.com/irj/scn/index?rid=/library/uuid/10e2502e-29f4-2f10-ab9a-d34504de3ed7&overridelayout=true

http://scn.sap.com/docs/DOC-31458


http://www.sdn.sap.com/irj/scn/index?rid=/library/uuid/10e2502e-29f4-2f10-ab9a-d34504de3ed7&overridelayout=true










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4. Step-by-Step Procedure

4.1 Open SAPGUI within ADTThis step is for opening the SAP GUI within ADT. You can skip this step if you want to directly work inSAP GUI instead of working in ADT as all the subsequent steps are SAP GUI based.

1. Open ABAP Development Tool (ADT) that is ABAP in Eclipse (AiE).

2. Go to the ABAP perspective.

3. Open the ABAP project corresponding to the ABAP AS where you want to create the ODataService using SAP NetWeaver Gateway. You may have to provide ABAP username andpassword if single sign-on is not enabled.

4. Press Ctrl + 6 or click on Open SAP GUI toolbar icon to open the SAP GUI within ADT. SAPGUI Launcher dialog appears. Choose OK to open SAP GUI within ADT.

4.2 Create Gateway ProjectFirst create a Gateway Project. Follow the steps below to create the project in SAP GUI / ABAP

Workbench.

1. Open transaction SEGW in SAP GUI. The transaction opens SAP NetWeaver Gateway ServiceBuilder.

2. Choose Create Project on the toolbar

3. Enter details in the Create Project dialog box.

i. Enter appropriate name for the field Project . In our example, project name used isZSAP_GW_SAMPLE_CONSUMING_CDS.

ii. Enter appropriate Description.

iii. Choose Local Object to create the Gateway project in the $TMP package. [If you want, youcan specify the package name in the field Package and then press Enter or chooseContinue]




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4.3 Create Entity TypeThe next logical step after creating the Gateway Project is to define the Data Model. In thiscase, define the structure by importing it from the DDIC entity / CDS view. Follow the stepsbelow to define the Data Model for the Gateway service.

1. Right- click Data Model as shown in the screenshot below

2. Choose Import > DDIC Structure.

3. In DDIC Import dialog, enter details:




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i. Select ABAP Structure as SEPMAPPS_CDS_OIR from the search help. This isthe ABAP Dictionary View name for the CDS ViewSEPM_CDS_OPEN_INVOICE_REDUCED. After selecting, press Enter .

ii. Check As Entity Type, if not checked.

iii. Enter the name of the Entity as OpenInvoice.iv. Set Usage for each of the fields as shown below:

Field Path Usage

MANDT Ignore

SO_ID Key

COMPANY_NAME Property

CURRENT_DUNNING_LEVEL Property

DUNLEV_LANGU Ignore

DUNLEV_DESCR Property

CURRENCY_CODE Key

GROSS_AMOUNT Ignore

4. You can now see the Entity Type OpenInvoice.




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Choose Save button in the SAP GUI.

4.4 Create Entity Set

1. Right-click Entity Sets and choose Create.




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2. Enter Entity Set Name as OpenInvoiceSet and EntityType Name as OpenInvoice.

3. Press Enter or click on the Continue button

4. You can now see the Entity Set OpenInvoiceSet created.

5. Click on Save button in the SAPGUI to save the changes.

4.5 Service ImplementationThe next step is to provide mapping between the CDS View and the Entity Set. In this step youwill model the service implementation.

1. Expand Service Implementation. You will find OpenInvoiceSet under Service Implementation.Right-click OpenInvoiceSet , which is under Service Implementation ( i.e. open context menu ofOpenInvoiceSet) and choose Map to Data Source.




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The Map to Data Source dialog box appears.

2. In the Map to Data Source dialog, enter the details as follows:

i. Choose Target System as Local .

ii. Choose Type as Business Entity .

iii. Provide CDS View name SEPM_CDS_OPEN_INVOICE_REDUCED with prefixCDS~ in the Name field. You can also search and select the CDS view in theavailable F4 help.




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iv. Press Enter or click on the Continue button.

3. The Mapping Editor with two panels appears. You can use this editor to map the data sourceelements (in our example, CDS View fields) to Entity Set properties.

4. Drag relevant data source elements (CDS view fields) from the right panel to properties of theEntity Type OpenInvoice, which is displayed in the left panel, one at a time. Instead of drag anddrop, you can also select data source elements for each of the properties of Entity TypeOpenInvoice using F4 functionality. The screenshot below shows CDS view fields that havebeen mapped to the properties of Entity Type OpenInvoice.




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5. Click on Save button in the SAPGUI to save the changes.

4.6 Generate Runtime ObjectsThe next step is to provide service implementation. In this step you will see that the GW Modeland Data Provider classes are being generated and the code for GET_ENTITY andGET_ENTITIES being automatically generated by the framework [i.e., zero coding].

1. Choose the button shown in the screenshot below for generating the runtime objects.

2. Model and Service Definition dialog appears displaying the default class names for ModelProvider and Data Provider. The dialog also shows default names for Technical Model and

Technical Service with version number. Keep all the defaults and press Enter or chooseContinue.




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3. Choose Local Object when Create Object Directory Entry dialog appears. This will generate thetwo Model Provider classes and the two Data Provider classes in $TMP package. Alternatively,you can also specify the package where you want to generate these classes and press Enter orchoose Continue.

4. You should now see the success messages displayed with generation of the classes. Theclasses appear under $TMP (or the package that you had chosen in the previous step).




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5. Open the class ZCL_ZSAP_GW_SAMPLE_CON_DPC (or the class name that you had givenfor data provider if you had changed the default class name. The default class name can bedifferent based on what Gateway project name has been provided by you in Create GatewayProject step) to see the service implementation. The following methods are generated with the

business logic implemented:

i. OPENINVOICESET_GET_ENTITY

ii. OPENINVOICESET_GET_ENTITYSET

OpenInvoiceSet is the name of the Entity Set. The methods above correspond toGetEntity and GetEntities of the Entity Set OpenInvoiceSet with Entity TypeOpenInvoice.

4.7 Service RegistrationThe next step is to register the Gateway Service with SAP NetWeaver Gateway Hub

System.1. For registering the service, double-click on Service Maintenance node and choose Register .

A warning dialog as shown below pops up. Choose Yes.

2. Enter System Alias where service should be deployed. In our example, register the service inthe same system, so enter the System Alias as LOCAL.




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Press Enter or choose Continue.

3. The Add Service dialog box with default values appear. Choose Local Object or type $TMP inthe Package Assignment field.

NOTE

You can also register the service in any other package. To register the service in a differentpackage, enter appropriate package details.

After Package Assignment , press Enter or choose Continue.




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The Registration Status column appears Green. This indicates successful registration ofthe Service with the Gateway Hub ( in the example Gateway Hub is LOCAL system) andto the Internet Communication Framework (ICF).

4.8 Testing Gateway Service1. After registering the service, choose Maintain.

2. In the Activate and Maintain Services screen, choose Gateway Client.

3. In the SAP NetWeaver Gateway Client window, test the OData services created using Gateway. Specify the HTTP method like GET , POST, PUT, and DELETE .

i. Specify the Gateway service URI.




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ii. Specify the HTTP Request body and view the HTTP Response.

In order to test the Gateway Service that you created, retain the URI specified in RequestURI field. Choose Execute.

You can see the HTTP Response for the Gateway Service.

4. To check the metadata, add $metadata to the URI i.e., /sap/opu/odata/sap/ZSAP_GW_SAMPLE_CONSUMING_CDS_SRV/$metadata. In this URI,ZSAP_GW_SAMPLE_CONSUMING_CDS_SRV corresponds to Technical Service name of theGateway Service. Choose Execute. You can see the properties of the Entity Type OpenInvoice and the Entity Set OpenInvoiceSet details.




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5. To check the result of the Entity Set in the Gateway Service, specify /sap/opu/odata/sap/ZSAP_GW_SAMPLE_CONSUMING_CDS_SRV/OpenInvoiceSet inRequest URI field and then choose Execute. The result shows the data of the CDS view. Thus,using this procedure it is possible to create Gateway Service in a modeled approach [with zerocoding]. Note that to see the records you must generate the data in EPM data model asspecified in the section Data Model .

6. To test single record fetch, based on the key combination of CURRENCY_CODE and SO_ID,specify/sap/opu/odata/sap/ZSAP_GW_SAMPLE_CONSUMING_CDS_SRV/OpenInvoiceSet(CurrencyCode='EUR',SoId='500034920') in Request URI field and then choose Execute. [In the URI,currency code is specified as EUR and SO_ID is specified as 500034920. Change the value asper the data generated in your system]. You can see that appropriate single record is fetchedfrom the service.




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5. Appendix

Appendix

5.1 Appendix A – Abbreviations

Abbreviation Description

ADT ABAP Development Tools

EPM Enterprise Procurement Model

NW NetWeaver

ABAP AS ABAP Application Server

SADL Service Adaptation Definition Language

CDS Core Data Services

TCD Total Cost of Development

GW Gateway

ICF Internet Communication Framework

BOPF Business Object Processing Framework

BOL Business Object Layer

URI Uniform Resource Identifier

5.2 Appendix B – References

ABAP Development Tools Tutorials - Learn how to use ABAP in Eclipse:http://scn.sap.com/docs/DOC-31815

The NetWeaver Enterprise Procurement Model - An Introduction to EPM:http://scn.sap.com/docs/DOC-31458

5.3 Appendix C –

Link to ABAP for SAP HANA ReferenceScenarios

ABAP for SAP HANA Reference Scenario - http://scn.sap.com/docs/DOC-35518

ABAP for SAP HANA Reference Scenario: Implementing Open Items Analysis using SAPFloorplan Manager - http://scn.sap.com/docs/DOC-47390

ABAP for SAP HANA Reference Scenario: Implementing Mobile based Open Items AnalysisUsing SAP UI5 and SAP Gateway Foundation Component - http://scn.sap.com/docs/DOC-47388
























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5.4 Appendix D- Links to SAP NetWeaver Gateway

Documents

SCN Link: http://scn.sap.com/community/netweaver-gateway

How-To Guides: http://scn.sap.com/docs/DOC-27405

http://scn.sap.com/community/netweaver-gateway










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