Introduction
Maybe all of you know what is a view in a database: a view is an entity that is not persistent; it is defined as the projection of other entities. In this H2G we are going to see how to build a special kind of view, a CDS (Core Data Service) View, which contains some new technology concepts called Annotations.
Let's move step by step.
What's CDS?
"CDS is an infrastructure layer for defining semantically rich data models, which are represented as CDS views. In a very basic way, CDS allows developers to define entity types (such as orders, business partners, or products) and the semantic relationships between them, which correspond to foreign key relationships in traditional entity relationship (ER) models. CDS is defined using a SQL-based data definition language (DDL) that is based on standard SQL with some additional concepts, such as associations, which define the relationships between CDS views, and annotations, which direct the domain-specific use of CDS artifacts."
In our case we are going to use CDS views combined with OData annotations.
"The term annotations implies attaching data to another piece of data. Annotations are used in different areas; one area would be the semantic annotations, which determines what the OData properties contain, e.g. a phone number, a part of a name or address, or something related to a calendar event or an analytic query. This type of annotations are important for the applications running on mobile devices to seamlessly integrate into contacts, calendar, and telephony.
The second area is the capability annotations that describe the possible interactions defined by OData's uniform interface and the supported parts of a concrete service. These annotations will tell whether an entity set allows inserts, updates, or deletes, whether it requires a filter or which properties can be used in filter expressions. They also advertise capabilities that go beyond the base set defined by OData, e.g. whether an entity set allows free-text search via an SAP-defined query option." (cit. OData Model Editor for SAP Web IDE)
This means that with annotations, which I've already talked about in my previous blog here, we can define, in the view itself, how data have to appear when we are consuming them.
In particular, if we build an app starting from Smart Templates, this can automatically get the information regarding how to display backend data, from the annotations specified in the CDS views on which the service is defined.
In this blog we are going to see exactly this: we will start by building a CDS view on the ABAP backend, we will define some annotations in the view, we will end by building an app from Smart Templates with SAP Web IDE and we will integrate the annotation information coming from the backend with some other annotations defined in the app itself.
This blog has been split in 3 parts:
| Link | Content |
|---|---|
| This part | Development tool installation and DDL Source creation |
| How to create Smart Templates annotations within CDS views - part 2 | Service registration and Smart Template creation in the NW Gateway and consumed by Smart Templates |
| How to create Smart Templates annotations within CDS views - part 3 | Enhancing the annotation |
Objective
If you have followed my previous blog on Smart Templates you have seen how to create a new Smart Templates app from scratch. The annotation file was created as a XML file in the application itself. Here we want to do the same: obtain the same result, the same final application, but putting as many annotations as possible in the CDS view and create only a very small annotation file in the app.
Prerequisites
- JRE version 1.6 or higher, 32-Bit or 64-Bit
- Eclipse Mars (4.5) or Luna (4.4)
- SAP GUI: SAP GUI for Windows 7.40 or SAP GUI for Java 7.40 for Apple Mac or Linux (SAP GUI Download)
- Microsoft VC Runtime
Steps
- Installation of Eclipse and its ADT plugin
- DDL Source creation
- Service registration and Smart Template creation in the NW Gateway and consumed by Smart Templates
- Configure HANA Cloud Connector and create a destination
- Create a new app from a Smart Template
- Enhancing the annotation
Step 1: Installation of Eclipse and its ADT plugin
In order to be able to create CDS Views you need first to configure your development environment. The development tool for this kind of object is Eclipse equipped with the SAP ADT plugin. In this chapter we are going to see how to prepare your development environment. Before you start I'm assuming you have already installed a JRE and a SAP Gui on your workstation. They are both needed for our environment. Eclipse can be downloaded directly from Eclipse Downloads
1 - Select one of the two versions you want to use, Luna or Mars (I'm using Mars in this guide), and download it on your workstation
2 - Extract it in the desired folder
3 - Run Eclipse by double clicking on its icon
4 - Choose for now the proposed workspace
5 - Go on Help --> Install new software
6 - Paste the link (https://tools.hana.ondemand.com/mars) (updated info can be found here) and click on Add; specify a name for this plugin and click on OK
7 - Select ABAP Development Tools for SAP NetWeaver and choose Next
8 - On the next wizard page, you get an overview of the features to be installed. Choose Next
9 - Confirm the license agreements and choose Finish to start the installation
10 - Restart Eclipse when required
11 - After restarting click on Go to Workbench
Step 2: DDL Source creation
In order to create a CDS View we first need to create a DDL Source. Such kind of object can be created in Eclipse by the following procedure:
1 - Create a new ABAP project by clicking on the menu File --> New --> Project --> ABAP --> ABAP Project and then click on Next
2 - Enter the System ID, the Application server and the Instance number and click on Next
3 - Enter the Client Number, the Username, the Password and the chosen Language then click Next
4 - Specify a name for the project or leave the proposed one then click on Finish
5 - You will be asked to open the ABAP Perspective. Answer Yes
6 - A default favorite local package should be already available for you. Right click on this package and choose New --> Other ABAP Repository Object. Type "ddl" in the filter box, choose DDL Source and click on Next
7 - Give a name to the DDL Source (i.e. Z_SAMPLE_DEMO_SOLI) and a description (i.e. Sample Demo Sales Orders Line Items) then click on Next
8 - Click again on Next at the Selection of Transport Request screen
9 - Use the template Define View and click on Next
10 - We are ready to create our first simple view. Paste the following code in the editor
@AbapCatalog.sqlViewName:'Z_VW_SOLITEMS'
@AbapCatalog.compiler.compareFilter:true
@AccessControl.authorizationCheck:#CHECK
@EndUserText.label:'Sales Order Line Items'
defineview Z_Sample_Demo_Soli
asselectfrom sepm_isoi as SOLItems
{
key SOLItems.salesorderitemuuid,
SOLItems.salesorderuuid as SalesOrderID,
SOLItems.salesorderitem as ItemPosition,
SOLItems.productuuid as ProductID,
SOLItems.shorttextgroupuuid as NoteID,
SOLItems.transactioncurrency as CurrencyCode,
SOLItems.grossamountintransaccurrency as GrossAmount,
SOLItems.netamountintransactioncurrency as NetAmount,
SOLItems.taxamountintransactioncurrency as TaxAmount,
SOLItems.productavailabilitystatus as StatusAvailability,
SOLItems.opportunityitem as OpportunityItem
}
11 - Save the file and activate it, you should not get any error
12 - You can test the view by pressing CTRL+F11 on Windows or by clicking on the green play button on the toolbar. When asked, choose to run the view as an ABAP Application. You should get something like this
13 - Repeat the same steps for creating a new DDL Source named Z_SAMPLE_DEMO_PRODUCTS with the description Sample Demo Products
14 - Paste this code in the view, save and activate it
@AbapCatalog.sqlViewName:'Z_VW_PRODUCTS'
@AbapCatalog.compiler.compareFilter:true
@AccessControl.authorizationCheck:#CHECK
@EndUserText.label:'Products'
defineview Z_Sample_Demo_Products
asselectfrom sepm_iproduct as Products
association[1..*]to Z_Sample_Demo_Soli as _SOItems on $projection.productuuid = _SOItems.ProductID
association[1..1]to sepm_iproductt as _ProductT on $projection.productuuid = _ProductT.productuuid
and _ProductT.language ='E'
association[1..1]to sepm_ibupa as _Supplier on $projection.supplieruuid = _Supplier.businesspartneruuid
{
key Products.productuuid,
Products.product as ProductID,
Products.producttype as TypeCode,
Products.productcategory as Category,
_ProductT.productname as Name,
'EN' as NameLanguage,
_ProductT.productdescription as Description,
'EN' as DescriptionLanguage,
_Supplier.businesspartner as SupplierID,
_Supplier.companyname as SupplierName,
Products.productvalueaddedtax as TaxTarifCode,
Products.productbaseunit as MeasureUnit,
Products.weight as WeightMeasure,
Products.weightunit as WeightUnit,
Products.currency as CurrencyCode,
Products.price as Price,
Products.width as Width,
Products.depth as Depth,
Products.height as Height,
Products.dimensionunit as DimUnit,
Products.creationdatetime as CreatedAt,
Products.lastchangeddatetime as ChangedAt,
concat(concat('/webapp/images/',Products.product),'.jpg') as PictureUrl,
Products.supplieruuid,
_SOItems
}
15 - You can test this view as well by pressing the play button
Let me spend a few words on these two views.
In the first view, Z_SAMPLE_DEMO_SOLI, I'm just selecting some fields form the EPM table sepm_isoi containing all the sales orders line items. I'm asserting that the key for this table is SOLItems.salesorderitemuuid and that the fields have some predefined names.
In the second view, Z_SAMPLE_DEMO_PRODUCTS, I'm creating an association between the table sepm_iproduct and the view defined earlier, so that for each product I can see all the sales order line items related to that product. Further to this I'm also doing another association with the table sepm_iproductt in order to get the name and the description of the product and with the sepm_ibupa to get some information about the business partner as well.
NOTE 1: probably you have noticed that I'm creating a PictureUrl column by concatenating the following 3 pieces:
'/webapp/images' the name of the product '.jpg'.
I did it in this way to reflect the work I did in my previous blog with smart templates. Of course you could extract the PictureUrl field directly from the database, but in this case, after creating the app in SAP Web IDE, you should add a new section in neo-app.json file to map the backend resource.
NOTE 2: at the end of the view you see I've also added "_SOItems": this means that I want to show also all the fields of the first view Z_SAMPLE_DEMO_SOLI. In this way, the service will present it as a new entity linked to the first one in the metadata.xml file.
Let's continue now with the second part of this blog to understand how to create a new service for this view and how to consume it in a Smart Template app.