SAP CDS Interview Questions and Answers

In the world of SAP development, Core Data Services (CDS) has emerged as a powerful infrastructure that allows developers to define and consume semantically rich data models in a standardized manner. With its unified syntax, SAP CDS simplifies data modeling and offers various advantages for efficient application development. In this article, we will explore some commonly asked SAP CDS interview questions to help you prepare for your next interview. Let's get started!

1. What is SAP CDS?

A: SAP Core Data Services (CDS) is an infrastructure that allows developers to define and consume semantically rich data models in a standardized manner. It provides a way to define database tables, views, and associations using a unified syntax.

2. What are the advantages of using SAP CDS?

A: SAP CDS offers several advantages, including:

• Simplified data modeling: With its unified syntax, CDS simplifies the process of defining data models, making it easier for developers to create and maintain complex data structures.
• Better performance: CDS optimizes access to the database, resulting in improved performance compared to traditional approaches. It leverages the power of underlying database platforms such as SAP HANA.
• Reusability of CDS artifacts: CDS artifacts, such as views and associations, can be reused across different applications, promoting consistency and reducing development efforts.
• Integration with other SAP technologies: CDS seamlessly integrates with other SAP technologies, such as SAP HANA and ABAP, allowing developers to leverage the full potential of the SAP ecosystem.

3. What are the different types of CDS views?

A: There are three main types of CDS views:

• Basic Views: These read-only views are used for reporting purposes. They provide a simple way to fetch data from underlying tables or views.
• Composite Views: Composite views are based on multiple underlying views and can include additional logic. They are used to build more complex views by combining and transforming data from multiple sources.
• Consumption Views: Consumption views are used for consuming data from external sources or exposing CDS views as OData services. They enable integration with external systems and provide a standardized way to access CDS views.

4. What is the difference between a CDS entity and a CDS view?

A: A CDS entity represents a database table or a projection of a table, while a CDS view is a logical representation of one or more entities or other views. CDS views can include joins, aggregations, and calculations, providing a more complex and business-oriented data model.

5. How can you restrict access to CDS views?

A: Access to CDS views can be restricted by implementing appropriate authorization checks in the ABAP code. By using authorization objects and authorization fields, you can control which users or roles have access to specific CDS views.

6. What is the difference between a CDS view and a database view?

A: While both CDS views and database views are used for data modeling, there are a few key differences:

• CDS views are defined in the ABAP Dictionary and provide a unified syntax for modeling both database and application-specific views. They offer advanced features such as associations, annotations, and built-in authorization checks.
• Database views are specific to the database system and are typically defined directly in the database. They may have a different syntax and limited features compared to CDS views.

7. What are annotations in CDS?

A: Annotations in CDS allow you to enhance the metadata of CDS artifacts, providing additional information to tools and frameworks. Annotations are defined using the.

8. What are associations in CDS views?

A: Associations in CDS views define relationships between entities or views. They allow you to express links between data based on keys or other conditions. Associations enable navigation from one entity to another, providing a convenient way to access related data.

9. How can you enhance CDS views with annotations?

A: CDS views can be enhanced with annotations to provide additional information about the structure and behavior of the views. Annotations can be used to define labels, descriptions, default values, and other metadata for fields, entities, and associations. They can also be used to control UI behavior and enable integration with other SAP technologies.

10. What is the difference between a CDS table function and a CDS view?

A: A CDS table function is a reusable function that returns a table as a result. It can be called like a regular database function, and the result can be consumed by other CDS views or ABAP programs. In contrast, a CDS view is a read-only projection of data that can be used for reporting and data retrieval but cannot be directly called as a function.

11. What is the purpose of CDS annotations @AbapCatalog.sqlViewName and @AbapCatalog.compiler.compareFilter?

A: The @AbapCatalog.sqlViewName annotation allows you to specify a custom name for the generated SQL view in the underlying database. This can be useful when you need to have a specific name for the view.

The @AbapCatalog.compiler.compareFilter annotation is used to control the filtering behavior during the activation of CDS views. It allows you to define filters that are applied during the comparison of data from the database and the activation version of the CDS view.

12. How can you consume a CDS view in an ABAP program?

A: To consume a CDS view in an ABAP program, you can use the OPEN SQL statement or the ABAP CDS view feature. With OPEN SQL, you can directly query the CDS view and retrieve the data into internal tables. With ABAP CDS view, you can define a data declaration and use the CDS view as a data source, allowing you to access the data using ABAP syntax.

13. What are the different types of joins supported in CDS views?

A: CDS views support various types of joins, including:

• Inner Join: Retrieves rows that have matching values in both tables.
• Left Outer Join: Retrieves all rows from the left table and the matching rows from the right table.
• Right Outer Join: Retrieves all rows from the right table and the matching rows from the left table.
• Full Outer Join: Retrieves all rows from both tables, matching rows where available.
• Cross Join: Retrieves the Cartesian product of both tables, combining each row from the left table with every row from the right table.

14. Can you create indexes on CDS views?

A: No, you cannot create indexes directly on CDS views. However, you can define secondary indexes on the underlying database table or use the indexing capabilities provided by the database system.

15. How can you expose a CDS view as an OData service?

A: You can expose a CDS view as an OData service by using the @OData.publish annotation. This annotation activates the OData service for the CDS view, making it available for consumption by external systems. Additionally, you can use the @OData.publish.urlAlias annotation to define a custom URL alias for the OData service.

16. What is the purpose of the @ObjectModel.text annotation in CDS views?

A: The @ObjectModel.text annotation is used to define a field as the textual representation of an entity. It is often used for descriptive fields that provide a meaningful description of an entity. This annotation helps in generating user-friendly labels and texts in the UI.

17. How can you restrict data access in CDS views?

A: Data access can be restricted in CDS views using the following techniques:

• Filtering: You can use the @ObjectModel.restrict annotation to apply filters to limit the data that is retrieved from the underlying tables.
• Authorization Checks: By implementing authorization checks in the ABAP code or using the @AccessControl.authorizationCheck annotation, you can control which users have access to specific data.
• Field-Level Authorization: You can use the @AccessControl.fieldLevel annotation to define field-level authorization checks, allowing certain fields to be visible or editable based on user roles or authorizations.

18. How can you handle runtime errors in CDS views?

A: Runtime errors in CDS views can be handled by implementing error handling mechanisms such as exception classes and error messages. By using the @AbapCatalog.errorHandling annotation, you can define error messages for specific scenarios or conditions. Additionally, you can use try-catch blocks in ABAP code to handle runtime exceptions gracefully.

19. What is the difference between a CDS view and a database view?

A: The main differences between a CDS view and a database view are as follows:

• CDS views are defined and managed within the ABAP layer, whereas database views are created directly in the database.
• CDS views can be consumed by both ABAP and non-ABAP systems, whereas database views are typically accessed only by the database itself.
• CDS views provide a higher level of abstraction and support advanced features such as annotations, associations, and aggregation, which are not available in traditional database views.

20. What is the purpose of the @Analytics annotations in CDS views?

A: The @Analytics annotations in CDS views are used to enable analytical capabilities and define analytical queries on the view. These annotations allow you to specify dimensions, measures, and other properties required for reporting and analysis purposes. They enable integration with SAP Analytics tools like SAP Fiori analytical apps and SAP BusinessObjects.

21. Can you use CDS views in ABAP Core Data Services (CDS) Data Models?

A: Yes, CDS views can be used in ABAP Core Data Services (CDS) Data Models. CDS views can be included as entities or associations within CDS Data Models, providing a reusable and modular approach to data modeling. This allows you to leverage existing CDS views and combine them with additional entities and associations to build comprehensive data models.

22. What is the difference between a CDS view and an AMDP (ABAP Managed Database Procedure)?

A: The main differences between a CDS view and an AMDP are as follows:

• CDS views are primarily used for data retrieval and reporting, whereas AMDPs are used to execute complex database operations and calculations.
• CDS views are defined using declarative annotations and can be consumed by various systems, whereas AMDPs are ABAP procedures written in ABAP language and executed in the database layer.
• CDS views can be used directly in ABAP programs and other CDS views, whereas AMDPs need to be explicitly called from ABAP code.

23. Can you define a CDS view without a database table as the data source?

A: Yes, it is possible to define a CDS view without a database table as the data source. CDS views can be based on multiple data sources, including other CDS views, database tables, or even function modules. This allows you to create views that combine and transform data from various sources to meet specific reporting or analytical requirements.

24. What is the difference between a CDS association and a join?

A: A CDS association represents a relationship between two entities in a CDS view, while a join is used to combine data from multiple tables based on a common field or condition. The main differences are:

• Associations are used to define relationships between entities, allowing navigation from one entity to another, while joins are used to retrieve data by combining rows from multiple tables.
• Associations can be defined using the @ObjectModel.association annotation in CDS views, whereas joins are specified in the SELECT statement using JOIN clauses.
• Associations can be used to retrieve related data in a hierarchical or structured manner, while joins combine rows based on common fields or conditions.

25. How can you enhance CDS views using CDS view extensions?

A: CDS view extensions allow you to enhance existing CDS views without modifying their original definitions. You can extend CDS views using the EXTEND VIEW statement, which allows you to add additional fields, annotations, associations, and projections to the base view. This approach helps to maintain the separation of concerns and promotes reusability.

26. What are the benefits of using CDS views over database views?

A: Some benefits of using CDS views over database views include:

• CDS views provide a higher level of abstraction and are defined within the ABAP layer, making them more flexible and portable across different database platforms.
• CDS views support advanced features such as annotations, associations, and aggregation, which are not available in traditional database views.
• CDS views can be consumed by both ABAP and non-ABAP systems, enabling integration with various applications and reporting tools.
• CDS views are part of the ABAP Core Data Services framework, which offers additional capabilities such as data access control, authorization checks, and lifecycle management.

27. Can you use CDS views for data manipulation (INSERT, UPDATE, DELETE) operations?

A: Yes, you can use CDS views for data manipulation operations such as INSERT, UPDATE, and DELETE. With the introduction of CDS Table Functions, you can define CDS views that are capable of modifying data in underlying database tables. CDS Table Functions combine the power of CDS views with data modification capabilities, allowing you to perform CRUD operations in a declarative manner.

28. What is the purpose of the @ObjectModel.compose annotation in CDS views?

A: The @ObjectModel.compose annotation is used to define a field as a composition link between two entities in a CDS view. It represents a parent-child relationship where the child entity is part of the parent entity's lifecycle. The @ObjectModel.compose annotation helps maintain the integrity and consistency of the relationship when inserting, updating, or deleting data.

29. How can you handle performance optimization in CDS views?

A: Performance optimization in CDS views can be achieved through various techniques, such as:

• Proper indexing of underlying database tables to improve query performance.
• Efficient use of joins and associations to minimize data retrieval.
• Filtering data at the earliest possible stage using the @ObjectModel.restrict annotation.
• Avoiding unnecessary calculations or transformations in the CDS view definition.
• Leveraging built-in aggregation functions for aggregations instead of retrieving and processing large datasets.

30. Can you consume CDS views in SAP HANA Calculation Views?

A: Yes, you can consume CDS views in SAP HANA Calculation Views. SAP HANA Calculation Views provide advanced modeling capabilities and allow you to combine data from various sources, including CDS views, database tables, and other Calculation Views. This integration enables you to leverage the advantages of CDS views within the SAP HANA data modeling environment.

31. What is the difference between CDS views and ABAP Dictionary views?

A: The main differences between CDS views and ABAP Dictionary views are:

• CDS views are defined in the ABAP layer using the Core Data Services framework, while ABAP Dictionary views are defined in the ABAP Dictionary.
• CDS views provide a higher level of abstraction and offer advanced features such as annotations, associations, and data access control, which are not available in ABAP Dictionary views.
• CDS views are portable and can be used across different database platforms, while ABAP Dictionary views are specific to the underlying database.
• CDS views can be consumed by both ABAP and non-ABAP systems, whereas ABAP Dictionary views are primarily used within the ABAP environment.

32. What is the purpose of the @ObjectModel.foreignKey annotation in CDS views?

A: The @ObjectModel.foreignKey annotation is used to define a foreign key relationship between two entities in a CDS view. It helps establish referential integrity and ensures that the values in the foreign key field correspond to valid entries in the referenced entity's primary key field.

33. How can you enable authorization checks in CDS views?

A: Authorization checks in CDS views can be enabled using the @AccessControl.authorizationCheck annotation. By applying this annotation to a CDS view, you can enforce access restrictions based on the user's authorization roles and permissions. The annotation defines the authorization object and fields that should be checked during data access.

34. What are CDS BOPF annotations?

A: CDS BOPF (Business Object Processing Framework) annotations are used to integrate CDS views with the BOPF framework. BOPF provides a model-driven approach for building and executing business processes in SAP systems. The CDS BOPF annotations allow you to define business object behavior, associations, validations, and actions directly in the CDS view definition, making it easier to create and manage business objects.

35. How can you use CDS views in SAP Analytics Cloud (SAC)?

A: CDS views can be consumed in SAP Analytics Cloud (SAC) for data visualization and analysis. You can establish a connection between SAC and the SAP system where the CDS views are defined. SAC allows you to import CDS views as data sources and create visualizations, dashboards, and reports based on the imported data. This integration provides real-time access to CDS view data in SAC and enables powerful data analytics capabilities.

36. What is the purpose of the @Semantics annotation in CDS views?

A: The @Semantics annotation is used to define the semantic meaning of fields in a CDS view. It provides additional information about the data, such as its purpose, usage, and behavior. The @Semantics annotation helps in data integration, reporting, and analysis by providing a standardized way to interpret and represent data across different systems.

37. Can you create CDS views without using ABAP Development Tools (ADT)?

A: No, CDS views cannot be created without using ABAP Development Tools (ADT). ADT provides the necessary tools and editors to define and manage CDS views within the ABAP environment. It offers features such as code completion, syntax validation, and metadata generation, which are essential for CDS view development.

38. What is the purpose of the @Analytics annotation in CDS views?

A: The @Analytics annotation is used to specify how a field in a CDS view should be treated in analytics scenarios. It allows you to define properties such as aggregatability, display format, and relevance for reporting and analysis purposes. The @Analytics annotation helps optimize the performance and usability of CDS views when used in analytical applications.

39. What is the purpose of the @Consumption annotation in CDS views?

A: The @Consumption annotation is used to define consumption-specific properties for CDS views. It allows you to specify how the CDS view should be consumed in different scenarios, such as reporting, data access, or user interfaces. The @Consumption annotation provides options for controlling access restrictions, input parameters, and output behavior of the CDS view.

40. What is a CDS table function?

A: A CDS table function is a type of CDS artifact that represents a database function returning tabular data. It allows you to define a reusable function interface in the CDS layer, which can be called like a regular table in ABAP code. CDS table functions can have input parameters and return a result set that can be used in subsequent operations.

41. What is the purpose of the @UI annotation in CDS views?

A: The @UI annotation is used to define the user interface (UI) properties and behavior of fields in a CDS view. It helps in enhancing the presentation and usability of CDS views in user interfaces like SAP Fiori applications. The @UI annotation allows you to specify properties such as labels, tooltips, field grouping, and formatting options for the fields.

42. What is the difference between CDS view and CDS table function?

A: The main difference between a CDS view and a CDS table function is that a CDS view represents a virtual table that can be queried directly, while a CDS table function represents a database function that returns a result set. CDS views are suitable for complex queries and reporting scenarios, whereas CDS table functions are used when you need to execute a reusable database function and retrieve tabular data as a result.

43. How can you debug a CDS view?

A: You can debug a CDS view by using the standard ABAP debugging tools available in the ABAP Development Tools (ADT) or the ABAP Debugger in the SAP GUI. To debug a CDS view, you need to set breakpoints in the ABAP code that calls or uses the CDS view, and then execute the program or application that triggers the CDS view execution. The debugger will pause at the breakpoints, allowing you to step through the code and analyze the data flow in the CDS view.

44. What are the benefits of using CDS views over database views?

A: Some benefits of using CDS views over traditional database views are:

• CDS views provide a higher level of abstraction and flexibility compared to database views.
• CDS views can be defined and consumed directly in the ABAP layer, eliminating the need for separate database-specific development.
• CDS views offer advanced features such as annotations, associations, and data access control, which are not available in traditional database views.
• CDS views are portable and can be used across different database platforms, whereas database views are specific to the underlying database.
• CDS views can be consumed by both ABAP and non-ABAP systems, making them suitable for integration scenarios.

45. Can you use CDS views in SAP HANA Calculation Views?

A: Yes, you can use CDS views in SAP HANA Calculation Views. SAP HANA Calculation Views are powerful modeling objects that allow you to combine and transform data from multiple sources. CDS views can be used as a source for SAP HANA Calculation Views, providing a convenient way to leverage the data modeling capabilities of both CDS and SAP HANA Calculation Views in a single solution.

46. What is the purpose of the @DefaultAggregation annotation in CDS views?

A: The @DefaultAggregation annotation is used to define the default aggregation behavior for measures in CDS views. It allows you to specify how a measure should be aggregated when no explicit aggregation is specified in a query. The @DefaultAggregation annotation provides options such as SUM, MIN, MAX, AVG, and more, allowing you to control the default behavior based on your requirements.

47. How can you expose CDS views as OData services?

A: To expose CDS views as OData services, you can use the SAP Gateway Service Builder (Transaction SEGW) or the SAP Cloud Platform, ABAP Environment. In the SAP Gateway Service Builder, you can create a new service project, define your CDS view as a data source, and generate the corresponding OData service based on the CDS view metadata. In the SAP Cloud Platform, ABAP Environment, you can create an ABAP RESTful Programming Model (RAP) project and define CDS views as part of the project, which automatically exposes them as OData services.

48. What is the purpose of the @ObjectModel annotation in CDS views?

A: The @ObjectModel annotation is used to control the object-oriented behavior of CDS views. It allows you to define properties such as the read-only status, key fields, and lifecycle status for entities in the CDS view. The @ObjectModel annotation enables object-oriented access to CDS views by treating them as business objects with properties, associations, and methods.

49. How can you enhance CDS views with custom logic?

A: You can enhance CDS views with custom logic by using CDS view extensions and CDS view annotations. CDS view extensions allow you to add additional fields, calculations or joins to an existing CDS view without modifying the original view. You can also use CDS view annotations to provide additional metadata or behavior to the existing CDS view. By leveraging these techniques, you can extend and customize the functionality of CDS views to meet specific requirements.

50. What is the difference between a CDS association and a CDS join?

A: The main difference between a CDS association and a CDS join is their purpose and behavior. A CDS association represents a logical relationship between two CDS views or entities, allowing you to navigate between them based on defined associations. It is used to establish a link between related entities and supports navigation operations. On the other hand, a CDS join is used to combine data from multiple tables or views based on common fields. It performs a join operation to retrieve the combined result set, but it does not establish a logical relationship like an association.

I hope you find these questions helpful for your interview preparation. If you have any more questions, feel free to ask!