C_ABAPD_2309 Questions and Answers

The following are the explanations for each statement:

• A: This statement is correct. go_subl = CAST #(go_super) will not work. This is because go_subl is a data object of type REF TO cl_subl, which is a reference to the subclass cl_subl. go_super is a data object of type REF TO cl_super, which is a reference to the superclass cl_super. The CAST operator is used to perform a downcast or an upcast of a reference variable to another reference variable of a compatible type. A downcast is a conversion from a more general type to a more specific type, while an upcast is a conversion from a more specific type to a more general type. In this case, the CAST operator is trying to perform a downcast from go_super to go_subl, but this is not possible, as go_super is not pointing to an instance of cl_subl, but to an instance of cl_super. Therefore, the CAST operator will raise an exception CX_SY_MOVE_CAST_ERROR at runtime12
• B: This statement is incorrect. go_sub2 = CAST #(go_super) will work. go_subl = CAST #(go_super) will not work. This is because go_sub2 is a data object of type REF TO cl_sub2, which is a reference to the subclass cl_sub2. go_super is a data object of type REF TO cl_super, which is a reference to the superclass cl_super. The CAST operator is used to perform a downcast or an upcast of a reference variable to another reference variable of a compatible type. A downcast is a conversion from a more general type to a more specific type, while an upcast is a conversion from a more specific type to a more general type. In this case, the CAST operator is trying to perform a downcast from go_super to go_sub2, and this is possible, as go_super is pointing to an instance of cl_sub2, which is a subclass of cl_super. Therefore, the CAST operator will assign the reference of go_super to go_sub2 without raising an exception. However, the CAST operator will not work for go_subl, as explained in statement A12
• C: This statement is incorrect. go_sub2 = CAST #(go_super) will work. go_sub2->sub2_meth1(…) will not work. This is because go_sub2 is a data object of type REF TO cl_sub2, which is a reference to the subclass cl_sub2. go_super is a data object of type REF TO cl_super, which is a reference to the superclass cl_super. The CAST operator is used to perform a downcast or an upcast of a reference variable to another reference variable of a compatible type. A downcast is a conversion from a more general type to a more specific type, while an upcast is a conversion from a more specific type to a more general type. In this case, the CAST operator is trying to perform a downcast from go_super to go_sub2, and this is possible, as go_super is pointing to an instance of cl_sub2, which is a subclass of cl_super. Therefore, the CAST operator will assign the reference of go_super to go_sub2 without raising an exception. However, the method call go_sub2->sub2_meth1(…) will not work, as sub2_meth1 is a subclass-specific method of cl_sub2, which is not inherited by cl_super. Therefore, the method call will raise an exception CX_SY_DYN_CALL_ILLEGAL_METHOD at runtime123
• D: This statement is correct. go_subl->subl_meth1(…) will work. This is because go_subl is a data object of type REF TO cl_subl, which is a reference to the subclass cl_subl. subl_meth1 is a subclass-specific method of cl_subl, which is not inherited by cl_super. Therefore, the method call go_subl->subl_meth1(…) will work, as go_subl is pointing to an instance of cl_subl, which has the method subl_meth1123

References: NEW - ABAP Keyword Documentation, CAST - ABAP Keyword Documentation, Method Call - ABAP Keyword Documentation

Using ABAP SQL, the select statement that selects the mat field on line #17 is:

SELECT mat FROM demo_sales_cds_so_i_ve…

This statement selects the mat field from the CDS view demo_sales_cds_so_i_ve, which is defined on line #1. The CDS view demo_sales_cds_so_i_ve is a projection view that projects the fields of the CDS view demo_sales_cds_so_i, which is defined on line #2. The CDS view demo_sales_cds_so_i is a join view that joins the fields of the database table demo_sales_so_i, which is defined on line #3, and the CDS view demo_sales_cds_material_ve, which is defined on line #4. The CDS view demo_sales_cds_material_ve is a value help view that provides value help for the material field of the database table demo_sales_so_i. The mat field is an alias for the material field of the database table demo_sales_so_i, which is defined on line #91.

The other options are not valid because:

• A. SELECT mat FROM Material… is not valid because Material is not a valid data source in the given code. There is no CDS view or database table named Material.
• C. SELECT mat FROM demo_sales_so_i… is not valid because demo_sales_so_i is not a valid data source in the given code. There is no CDS view named demo_sales_so_i, only a database table. To access a database table, the keyword TABLE must be used, such as SELECT mat FROM TABLE demo_sales_so_i…
• D. SELECT mat FROM demo sales cds material ve… is not valid because demo sales cds material ve is not a valid data source in the given code. There is no CDS view or database table named demo sales cds material ve. The correct name of the CDS view is demo_sales_cds_material_ve, with underscores instead of spaces.

References: 1: Projection Views - ABAP Keyword Documentation

The code snippet in the image is an example of using the RAISE EXCEPTION statement to raise a class-based exception and create a corresponding exception object. The code snippet also uses the EXPORTING addition to pass parameters to the instance constructor of the exception class12. Some of the valid statements about the code snippet are:

• The code creates an exception object and raises an exception: This is true. The RAISE EXCEPTION statement raises the exception linked to the exception class zcxl and generates a corresponding exception object. The exception object contains the information about the exception, such as the message, the source position, and the previous exception12.
• “previous” expects the reference to a previous exception: This is true. The previous parameter is a predefined parameter of the instance constructor of the exception class cx_root, which is the root class of all class-based exceptions. The previous parameter expects the reference to a previous exception object that was caught during exception handling. The previous parameter can be used to chain multiple exceptions and preserve the original cause of the exception12.

You cannot do any of the following:

• “zcxl” is a dictionary structure, and “paraml” and “param2” are this structure: This is false. zcxl is not a dictionary structure, but a user-defined exception class that inherits from the predefined exception class cx_static_check. param1 and param2 are not components of this structure, but input parameters of the instance constructor of the exception class zcxl. The input parameters can be used to pass additional information to the exception object, such as the values that caused the exception12.
• “paraml” and “param2” are predefined names: This is false. param1 and param2 are not predefined names, but user-defined names that can be chosen arbitrarily. However, they must match the names of the input parameters of the instance constructor of the exception class zcxl. The names of the input parameters can be declared in the interface of the exception class using the RAISING addition12.

References: 1: RAISE EXCEPTION - ABAP Keyword Documentation - SAP Online Help 2: Class-Based Exceptions - ABAP Keyword Documentation - SAP Online Help

SAP recommends that you eliminate the following types of legacy code when you review modifications as part of an SAP S/4HANA system conversion:

• Code that now is identical to a standard SAP object. This type of code is redundant and unnecessary, as it does not provide any additional functionality or customization. It can also cause conflicts or errors during the system conversion, as the standard SAP object may have changed or been replaced in SAP S/4HANA. Therefore, you should delete this type of code and use the standard SAP object instead.
• Code that can be redesigned as a key user extension. This type of code is usually related to UI or business logic adaptations that can be achieved using the in-app tools provided by SAP S/4HANA. By redesigning this type of code as a key user extension, you can simplify and standardize your code base, reduce maintenance efforts, and avoid compatibility issues during the system conversion. Therefore, you should migrate this type of code to the key user extensibility framework and delete the original code.

The other types of legacy code are not recommended to be eliminated, as they may still be relevant or necessary for your business processes. However, you should still review and adjust them according to the SAP S/4HANA simplification items and best practices. These types of code are:

• Code that supports a critical business process. This type of code is essential for your business operations and cannot be easily replaced or removed. However, you should check if this type of code is compatible with SAP S/4HANA, and if not, you should adapt it accordingly. You should also consider if this type of code can be optimized or enhanced using the new features and capabilities of SAP S/4HANA.
• Code that has less than 10% usage according to usage statistics. This type of code is rarely used and may not be worth maintaining or converting. However, you should not delete this type of code without verifying its relevance and impact on your business processes. You should also consider if this type of code can be replaced or consolidated with other code that has higher usage or better performance.

References: Custom Code Management (CCM) During an SAP S/4HANA Conversion, Custom Code Migration Guide for SAP S/4HANA 2020

When processing a loop with the statement DO… ENDDO, the system variable that contains the implicit loop counter is sy-index. The loop counter is a numeric value that indicates how many times the loop has been executed. The loop counter is initialized to 1 before the first execution of the loop and is incremented by 1 after each execution. The loop counter can be used to control the number of loop iterations or to access the loop elements by index. The loop counter can also be accessed or modified within the loop body, but this is not recommended as it may cause unexpected results or errors1.

For example, the following code snippet uses the loop counter sy-index to display the numbers from 1 to 10:

DO 10 TIMES. WRITE: / sy-index. ENDDO.

The output of this code is:

1 2 3 4 5 6 7 8 9 10

References: 1: DO - ABAP Keyword Documentation

• Use public SAP APIs and SAP extension points. This rule ensures that the ABAP Cloud code is stable, reliable, and compatible with the SAP solutions and the cloud operations. Public SAP APIs and SAP extension points are the only allowed interfaces and objects to access the SAP platform and the SAP applications. They are documented, tested, and supported by SAP. They also guarantee the lifecycle stability and the upgradeability of the ABAP Cloud code1.
• Build ABAP RESTful application programming model-based services. This rule ensures that the ABAP Cloud code follows the state-of-the-art development paradigm for building cloud-ready business services. The ABAP RESTful application programming model (RAP) is a framework that provides a consistent end-to-end programming model for creating, reading, updating, and deleting (CRUD) business data. RAP also supports draft handling, authorization checks, side effects, validations, and custom actions. RAP exposes the business services as OData services that can be consumed by SAP Fiori apps or other clients2.

The annotation @Environment.systemField: #LANGUAGE is used to assign the ABAP system field sy-langu to an input parameter of a CDS view or a CDS table function. This enables the implicit parameter passing in Open SQL, which means that the value of sy-langu will be automatically passed to the CDS view without explicitly specifying it in the WHERE clause. This also applies to the CDS views that use the annotated CDS view as a data source, which means that the value of sy-langu will be propagated to the nested CDS views (view on view)12. For example:

• The following code snippet defines a CDS view ZI_FLIGHT_TEXTS with an input parameter p_langu that is annotated with @Environment.systemField: #LANGUAGE:

define view ZI_FLIGHT_TEXTS with parameters p_langu : syst_langu @

• The following code snippet shows how to use the CDS view ZI_FLIGHT_TEXTS in ABAP without specifying the value of p_langu in the WHERE clause. The value of sy-langu will be automatically passed to the CDS view:

SELECT carrid, connid, fldate, carrname, carrtext FROM zi_flight_texts INTO TABLE @DATA(lt_flights).

• The following code snippet shows how to use the CDS view ZI_FLIGHT_TEXTS in another CDS view ZI_FLIGHT_REPORT. The value of sy-langu will be automatically passed to the nested CDS view ZI_FLIGHT_TEXTS:

define view ZI_FLIGHT_REPORT with parameters p_langu : syst_langu @

The annotation @Environment.systemField: #LANGUAGE does not prevent the possibility of overriding the default value with a value of your own. You can still specify a different value for the input parameter p_langu in the WHERE clause, either in ABAP or in another CDS view. This will override the value of sy-langu and pass the specified value to the CDS view12. For example:

• The following code snippet shows how to use the CDS view ZI_FLIGHT_TEXTS in ABAP with a specified value of p_langu in the WHERE clause. The value ‘E’ will be passed to the CDS view instead of the value of sy-langu:

SELECT carrid, connid, fldate, carrname, carrtext FROM zi_flight_texts WHERE p_langu = ‘E’ INTO TABLE @DATA(lt_flights).

• The following code snippet shows how to use the CDS view ZI_FLIGHT_TEXTS in another CDS view ZI_FLIGHT_REPORT with a specified value of p_langu in the WHERE clause. The value ‘E’ will be passed to the nested CDS view ZI_FLIGHT_TEXTS instead of the value of sy-langu:

define view ZI_FLIGHT_REPORT with parameters p_langu : syst_langu @

References: 1: ABAP CDS - parameter_annot - ABAP Keyword Documentation - SAP Online Help 2: ABAP CDS - session_variable - ABAP Keyword Documentation - SAP Online Help

The ABAP Cloud Development Model requires that only public SAP APIs and extension points are used to access SAP functionality and data. These APIs and extension points are released by SAP and documented in the SAP API Business Hub1. Customer-created function modules are not part of the public SAP APIs and are not released for cloud development. Therefore, calling a function module directly from an ABAP Cloud class is not allowed and will result in a syntax error. However, there are two possible ways to call a function module indirectly from an ABAP Cloud class:

• Create a wrapper class or interface for the function module and release it for cloud development. A wrapper is a class or interface that encapsulates the function module and exposes its functionality through public methods or attributes. The wrapper must be created in a software component with the language version set to “Standard ABAP” and must be marked as released for cloud development using the annotation @EndUserText.label. The wrapper can then be called from an ABAP Cloud class using the public methods or attributes2.
• Use the ABAP Cloud Connector to call the function module as a remote function call (RFC) from an ABAP Cloud class. The ABAP Cloud Connector is a service that enables the secure and reliable communication between SAP BTP, ABAP environment and on-premise systems. The function module must be exposed as an RFC-enabled function module in the on-premise system and must be registered in the ABAP Cloud Connector. The ABAP Cloud class can then use the class cl_rfc_destination_service to get the destination name and the class cl_abap_system to create a proxy object for the function module. The proxy object can then be used to call the function module3.

References: 1: SAP API Business Hub 2: Creating an ABAP Cloud Project | SAP Help Portal 3: Calling Remote Function Modules | SAP Help Portal

A projection view is a RESTful Application Programming object that contains only the fields required for a particular app. A projection view is a CDS view entity that defines a projection on an existing CDS view entity or CDS DDIC-based view. A projection view exposes a subset of the elements of the projected entity, which are relevant for a specific business service. A projection view can also define aliases, virtual elements, and annotations for the projected elements. A projection view is the top-most layer of a CDS data model and prepares data for a particular use case. A projection view can have different provider contracts depending on the type of service it supports, such as transactional query, analytical query, or transactional interface.

A database view is a CDS DDIC-based view that defines a join or union of database tables. A database view has an SQL view attached and can be accessed by Open SQL or native SQL. A database view can be used as a projected entity for a projection view, but it does not contain only the fields required for a particular app.

A metadata extension is a RESTful Application Programming object that defines additional annotations for a CDS view entity or a projection view. A metadata extension can be used to enhance the metadata of a CDS data model without changing the original definition. A metadata extension does not contain any fields, but only annotations.

A data model view is a CDS view entity that defines a data model based on database tables or other CDS view entities. A data model view can have associations, aggregations, filters, parameters, and annotations. A data model view can be used as a projected entity for a projection view, but it does not contain only the fields required for a particular app.

References: CDS Projection Views - ABAP Keyword Documentation, CDS Projection Views in ABAP CDS: What’s Your Flavor, Business Object Projection - ABAP Keyword Documentation

The ABAP SQL clause that allows the use of inline declarations is the INTO clause. The INTO clause is used to specify the target variable or field symbol where the result of the SQL query is stored. The INTO clause can use inline declarations to declare the target variable or field symbol at the same position where it is used, without using a separate DATA or FIELD-SYMBOLS statement. The inline declaration is performed using the DATA or @DATA operators in the declaration expression12. For example:

• The following code snippet uses the INTO clause with an inline declaration to declare a local variable itab and store the result of the SELECT query into it:

SELECT * FROM scarr INTO TABLE @DATA (itab).

• The following code snippet uses the INTO clause with an inline declaration to declare a field symbol and store the result of the SELECT query into it:

SELECT SINGLE * FROM scarr INTO @.

You cannot do any of the following:

• FROM: The FROM clause is used to specify the data source of the SQL query, such as a table, a view, or a join expression. The FROM clause does not allow the use of inline declarations12.
• INTO CORRESPONDING FIELDS OF: The INTO CORRESPONDING FIELDS OF clause is used to specify the target structure or table where the result of the SQL query is stored. The INTO CORRESPONDING FIELDS OF clause does not allow the use of inline declarations. The target structure or table must be declared beforehand using a DATA or FIELD-SYMBOLS statement12.
• FIELDS: The FIELDS clause is used to specify the columns or expressions that are selected from the data source of the SQL query. The FIELDS clause does not allow the use of inline declarations. The FIELDS clause must be followed by an INTO clause that specifies the target variable or field symbol where the result is stored12.

References: 1: SELECT - ABAP Keyword Documentation - SAP Online Help 2: Inline Declarations - ABAP Keyword Documentation - SAP Online Help

The correct ON condition that must be inserted in place of “???” is:

ON Sprojection.carrier_id=Z_Source2.carrier_id

This ON condition specifies the join condition between the CDS view Sprojection and the database table Z_Source2. The join condition is based on the field carrier_id, which is the primary key of both the CDS view and the database table. The ON condition ensures that only the records that have the same value for the carrier_id field are joined together1.

The other options are not valid ON conditions, because:

• A. ON Z_Sourcel.camer_id = 7_Source2 carrier_id is not valid because Z_Sourcel and 7_Source2 are not valid data sources in the given code. There is no CDS view or database table named Z_Sourcel or 7_Source2. The correct names are Z_Source1 and Z_Source2. Moreover, the field camer_id is not a valid field in the given code. There is no field named camer_id in any of the data sources. The correct name is carrier_id.
• B. ON Sprojection Camer=Source2 carrier_id is not valid because Sprojection and Source2 are not valid data sources in the given code. There is no CDS view or database table named Sprojection or Source2. The correct names are Sprojection and Z_Source2. Moreover, the field Camer is not a valid field in the given code. There is no field named Camer in any of the data sources. The correct name is carrier_id. Furthermore, the ON condition is missing the dot (.) operator between the data source name and the field name, which is required to access the fields of the data source1.
• C. ON Sprojection. Carrier Source2.carrier is not valid because Carrier and carrier are not valid fields in the given code. There is no field named Carrier or carrier in any of the data sources. The correct name is carrier_id. Moreover, the ON condition is missing the dot (.) operator between the data source name and the field name, which is required to access the fields of the data source1.

References: 1: ON Condition - ABAP Keyword Documentation

The sub constructor is the instance constructor of the subclass sub that inherits from the superclass super. The sub constructor has some rules that it must follow when it is defined and implemented12. Some of the valid rules are:

• The method signature can be changed: This is true. The sub constructor can have a different method signature than the super constructor, which means that it can have different input parameters, output parameters, or exceptions. However, the sub constructor must still call the super constructor with appropriate actual parameters that match its interface12.
• The constructor of super must be called before using any components of your own instance: This is true. The sub constructor must ensure that the super constructor is called explicitly using super->constructor before accessing any instance components of its own class, such as attributes or methods. This is because the super constructor initializes the inherited components of the subclass and sets the self-reference me-> to the current instance12.

You cannot do any of the following:

• Import parameters can only be evaluated after calling the constructor of super: This is false. The sub constructor can evaluate its own import parameters before calling the constructor of super, as long as it does not access any instance components of its own class. For example, the sub constructor can use its import parameters to calculate some values or check some conditions that are needed for calling the super constructor12.
• Events of your own instance cannot be raised before the registration of a handler in super: This is false. The sub constructor can raise events of its own instance before calling the constructor of super, as long as it does not access any instance components of its own class. For example, the sub constructor can raise an event to notify the consumers of the subclass about some status or error that occurred during the initialization of the subclass12.

References: 1: Inheritance and Constructors - ABAP Keyword Documentation - SAP Online Help 2: Using Static and Instance constructor methods | SAP Blogs

 Core Data Services (CDS) are preferable to the classical approach to data modeling for several reasons, but two of them are:

• They implement code pushdown. Code pushdown is the principle of moving data-intensive logic from the application server to the database server, where the data resides. This reduces the data transfer between the application server and the database server, which improves the performance and scalability of the application. CDS enable code pushdown by allowing the definition of semantic data models and business logic in the database layer, using SQL and SQL-based expressions1.
• They transfer computational results to the application server. CDS allow the application server to access the data and the logic defined in the database layer by using Open SQL statements. Open SQL is a standardized and simplified subset of SQL that can be used across different database platforms. Open SQL statements are translated into native SQL statements by the ABAP runtime environment and executed on the database server. The results of the computation are then transferred to the application server, where they can be further processed or displayed2.

References: 1: ABAP - Core Data Services (ABAP CDS) - ABAP Keyword Documentation 2: Open SQL - ABAP Keyword Documentation

In a RESTful Application Programming (RAP) application, you can bind a CDS view to create a value help in the following objects:

• Data model view: A data model view is a CDS view that defines the data structure and the associations of an entity in the RAP application. You can use the annotation @Consumption.valueHelpDefinition to bind a value help provider CDS view to an element of the data model view. The value help provider CDS view must contain the key fields of the value help entity and the fields that are displayed in the value help dialog. The value help annotation specifies the entity name, the element name, and optionally the additional binding conditions for the value help provider1.
• Metadata Extension: A metadata extension is a CDS view that extends the metadata of another CDS view without changing its data structure. You can use the annotation @MetadataExtension.extendView to specify the target CDS view that you want to extend. You can then use the same annotation @Consumption.valueHelpDefinition to bind a value help provider CDS view to an element of the target CDS view. The metadata extension allows you to add value help definitions to existing CDS views without modifying them2.
• Projection View: A projection view is a CDS view that defines the projection of another CDS view. You can use the annotation @AbapCatalog.sqlViewType: #PROJECTION to specify that the CDS view is a projection view. You can then use the same annotation @Consumption.valueHelpDefinition to bind a value help provider CDS view to an element of the projection view. The projection view allows you to add value help definitions to projected elements of another CDS view3.

You cannot bind a value help provider CDS view to a behavior definition or a service definition, because these objects do not define the data structure or the metadata of an entity in the RAP application. A behavior definition defines the behavior and the validation rules of an entity, such as the create, read, update, and delete (CRUD) operations, the draft handling, the authorization checks, and the side effects4. A service definition defines the service exposure and the service binding of an entity, such as the protocol, the version, the namespace, and the service name5.

References: 1: Value Help with Additional Binding | SAP Help Portal 2: Metadata Extensions - ABAP Keyword Documentation 3: Projection Views - ABAP Keyword Documentation 4: Behavior Definition - ABAP Keyword Documentation 5: Service Definition - ABAP Keyword Documentation

The response will be an activation error because the field names of the union do not match. This is because the field names of the union must match in order for the definition to be activated. The union operator combines the result sets of two or more queries into a single result set. The queries that are joined by the union operator must have the same number and type of fields, and the fields must have the same names1. In the given code, the field names of the union do not match, because the first query has the fields carrname, connid, cityfrom, and cityto, while the second query has the fields carrname, carrier_id, cityfrom, and cityto. The field connid in the first query does not match the field carrier_id in the second query. Therefore, the definition cannot be activated.

References: 1: UNION - ABAP Keyword Documentation

The following are the explanations for each action:

• A: Renaming a field in a structure that is included in the table definition causes an indirect change to the database table, as the field name in the table is derived from the structure. This change requires a table conversion, as the existing data in the table must be copied to a new table with the new field name, and the old table must be deleted.
• B: Changing the field labels of a data element that is used in the table definition does not cause an indirect change to the database table, as the field labels are only used for documentation and display purposes. This change does not require a table conversion, as the existing data in the table is not affected by the change.
• C: Deleting a field from a structure that is included in the table definition causes an indirect change to the database table, as the field is removed from the table as well. This change requires a table conversion, as the existing data in the table must be copied to a new table without the deleted field, and the old table must be deleted.
• D: Shortening the length of a domain used in a data element that is used in the table definition causes an indirect change to the database table, as the field length in the table is derived from the domain. This change requires a table conversion, as the existing data in the table must be checked for compatibility with the new field length, and any data that exceeds the new length must be truncated or rejected.

References: Converting Database Tables - ABAP Keyword Documentation, Adjustment of Database Structures - ABAP Keyword Documentation

The function find_any_not_of returns the position of the first character in the string val that is not contained in the string sub. If no such character is found, the function returns 0. In this case, the string val contains only the characters A, B, and a, which are all contained in the string sub, so the function returns 0. The other functions return positive values, as follows:

• Count_any_of returns the number of occurrences of any character in the string sub within the string val. In this case, it returns 8, since there are 8 A’s and B’s in val.
• Count returns the number of occurrences of the string sub within the string val. In this case, it returns 2, since there are 2 AB’s in val.
• find_any_of returns the position of the first character in the string val that is contained in the string sub. In this case, it returns 1, since the first character A is in sub. References: String Functions - ABAP Keyword Documentation, Examples of String Functions - ABAP Keyword Documentation

The purpose of a foreign key relationship between two tables in the ABAP Dictionary is to ensure the integrity of data in the corresponding database tables. A foreign key relationship defines a logical link between a foreign key table and a check table, where the foreign key fields of the former are assigned to the primary key fields of the latter. This means that the values entered in the foreign key fields must exist in the check table, otherwise the system will reject the entry. This way, the foreign key relationship prevents the insertion of invalid or inconsistent data in the database tables.

A foreign key relationship also serves to document the relationship between the two tables in the ABAP Dictionary, but this is not its primary purpose. A foreign key relationship does not necessarily create a corresponding foreign key relationship in the database, as this depends on the database system and the settings of the ABAP Dictionary. Some database systems do not support foreign keys at all, while others require additional steps to activate them. Therefore, the foreign key relationship in the ABAP Dictionary is mainly a logical concept that is enforced by the ABAP runtime environment.

References: Foreign Keys (SAP Library - ABAP Dictionary), Foreign Keys (SAP Library - BC - ABAP Dictionary)

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