Online C-ABAPD-2309 Test Brain Dump Question and Test Engine [Q20-Q41]

Explanation
String functions are expressions that can be used to manipulate character-like data in ABAP. String functions can be either predicate functions or non-predicate functions. Predicate functions are string functions that return a truth value (true or false) for a condition of the argument text. Non-predicate functions are string functions that return a character-like result for an operation on the argument text1.
The following string functions are predicate functions:
B). contains_any_of(): This function returns true if the argument text contains at least one of the characters specified in the character set. For example, the following expression returns true, because the text ‘ABAP’ contains at least one of the characters ‘A’, ‘B’, or ‘C’:
contains_any_of( val = ‘ABAP’ set = ‘ABC’ ).
D). matches(): This function returns true if the argument text matches the pattern specified in the regular expression. For example, the following expression returns true, because the text ‘ABAP’ matches the pattern that consists of four uppercase letters:
matches( val = ‘ABAP’ regex = ‘[A-Z]{4}’ ).
The following string functions are not predicate functions, because they return a character-like result, not a truth value:
A). find_any_not_of(): This function returns the position of the first character in the argument text that is not contained in the character set. If no such character is found, the function returns 0. For example, the following expression returns 3, because the third character of the text ‘ABAP’ is not contained in the character set ‘ABC’:
find_any_not_of( val = ‘ABAP’ set = ‘ABC’ ).
C). count_any_of(): This function returns the number of characters in the argument text that are contained in the character set. For example, the following expression returns 2, because there are two characters in the text ‘ABAP’ that are contained in the character set ‘ABC’:
count_any_of( val = ‘ABAP’ set = ‘ABC’ ).
References: 1: String Functions – ABAP Keyword Documentation

Database tables are data structures that store information in two dimensions, using rows and columns. Each row represents a record or an entity, and each column represents an attribute or a field. Database tables may have key fields, which are columns that uniquely identify each row or a subset of rows. Key fields can be used to enforce data integrity, perform efficient searches, and establish relationships to other tables. Database tables can have relationships to other tables, which are associations or links between the key fields of two or more tables. Relationships can be used to model the logical connections between different entities, join data from multiple tables, and enforce referential integrity12.

Explanation
The function module ZF1 is in a software component with the language version set to “ABAP Cloud”. This means that it follows the ABAP Cloud Development Model, which requires the usage of public SAP APIs and extension points 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 a class with the language version set to “Standard ABAP” is not allowed and will result in a syntax error.
However, there is a possible way to call a function module indirectly from a class with the language version set to “Standard ABAP”:
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 “ABAP Cloud” and must be marked as released for cloud development using the annotation @EndUserText.label. The wrapper can then be called from a class with the language version set to “Standard ABAP” using the public methods or attributes2.
For example, the following code snippet shows how to create a wrapper class for the function module ZF1 and call it from the class zcl_demo_class:
@EndUserText.label: ‘Wrapper for ZF1’ CLASS zcl_wrapper_zf1 DEFINITION PUBLIC FINAL CREATE PUBLIC. PUBLIC SECTION. CLASS-METHODS: call_zf1 IMPORTING iv_a TYPE i iv_b TYPE i EXPORTING ev_result TYPE i. ENDCLASS.
CLASS zcl_wrapper_zf1 IMPLEMENTATION. METHOD call_zf1. CALL FUNCTION ‘ZF1’ EXPORTING a = iv_a b = iv_b IMPORTING result = ev_result. ENDMETHOD. ENDCLASS.
CLASS zcl_demo_class DEFINITION. METHODS: m1. ENDCLASS.
CLASS zcl_demo_class IMPLEMENTATION. METHOD m1. DATA(lv_result) =
zcl_wrapper_zf1=>call_zf1( iv_a = 2 iv_b = 3 ). WRITE: / lv_result. ENDMETHOD. ENDCLASS.
The output of this code is:
5
References: 1: SAP API Business Hub 2: Creating an ABAP Cloud Project | SAP Help Portal

Explanation
The following are the explanations for each ABAP SQL statement:
A: This statement is valid. It selects the fields carrid, airpfrom, and the aggregate functions MAX(distance) and MIN(distance) from the table /dmo/connection, and groups the results by carrid and airpfrom. The aggregate functions are aliased as dist_max and dist_min. The results are stored in an internal table named It_hits, which is created using the inline declaration operator @DATA.
B: This statement is valid. It is similar to statement A, except that it does not specify the GROUP BY clause. This means that the aggregate functions are applied to the entire table, and the results are stored in an internal table named It_hits, which is created using the inline declaration operator @DATA.
C: This statement is invalid. It selects the aggregate functions MAX(distance) and MIN(distance) from the table /dmo/connection, but it does not specify any grouping or non-aggregate fields. This is not allowed in ABAP SQL, as the SELECT list must contain at least one non-aggregate field or a GROUP BY clause. The statement will cause a syntax error.
D: This statement is invalid. It selects the fields carrid and airpfrom from the table /dmo/connection, and groups the results by carrid and connid. However, the field connid is not included in the SELECT list, which is not allowed in ABAP SQL, as the GROUP BY clause must contain only fields that are also in the SELECT list. The statement will cause a syntax error.
References: SELECT – ABAP Keyword Documentation, GROUP BY – ABAP Keyword Documentation

Explanation
The following are the explanations for each statement:
C: This statement is valid. Class CL1 uses the interface. This is because class CL1 implements the interface ifl using the INTERFACES statement in the public section of the class definition. The INTERFACES statement makes the class compatible with the interface and inherits all the components of the interface. The class can then use the interface components, such as the method ml, by using the interface component selector ~, such as ifl~ml12 E: This statement is valid. Class CL1 implements the interface. This is because class CL1 implements the interface ifl using the INTERFACES statement in the public section of the class definition. The INTERFACES statement makes the class compatible with the interface and inherits all the components of the interface. The class must then provide an implementation for the interface method ml in the implementation part of the class, unless the method is declared as optional or abstract12 D: This statement is valid. In class CL2, the interface method is named ifl~ml. This is because class CL2 has a data member named m0_ifl of type REF TO ifl, which is a reference to the interface ifl. The interface ifl defines a method ml, which can be called using the reference variable m0_ifl. The interface method ml has the name ifl~ml in the class, where ifl is the name of the interface and the character ~ is the interface component selector12 The other statements are not valid, as they have syntax errors or logical errors. These statements are:
A: This statement is not valid. In class CL1, the interface method is named ifl~ml, not if-ml. This is because class CL1 implements the interface ifl using the INTERFACES statement in the public section of the class definition. The interface ifl defines a method ml, which can be called using the class name or a reference to the class. The interface method ml has the name ifl~ml in the class, where ifl is the name of the interface and the character ~ is the interface component selector. Using the character – instead of the character ~ will cause a syntax error12 B: This statement is not valid. Class CL2 does not use the interface, but only has a reference to the interface. This is because class CL2 has a data member named m0_ifl of type REF TO ifl, which is a reference to the interface ifl. The interface ifl defines a method ml, which can be called using the reference variable m0_ifl. However, class CL2 does not implement the interface ifl, nor does it inherit the interface components. Therefore, class CL2 does not use the interface, but only references the interface12 References: INTERFACES – ABAP Keyword Documentation, CLASS – ABAP Keyword Documentation

Explanation
Based on the following code, the variable type of connection_full is a structure. A structure is a complex data type that consists of a group of related data objects, called components, that have their own data types and names. A structure can be defined using the TYPES statement or based on an existing structure type, such as a CDS view entity or a CDS DDIC-based view. In this case, the variable connection_full is declared using the TYPE addition, which means that it has the same structure type as the CDS view entity /DMO/I_Connection.
The CDS view entity /DMO/I_Connection is a data model view that defines a data model based on the database table /DMO/Connection. The CDS view entity /DMO/I_Connection has the following components:
carrid, connid, airpfrom, airpto, distance, and fltime. Therefore, the variable connection_full has the same components as the CDS view entity /DMO/I_Connection, and each component has the same data type and length as the corresponding field in the database table /DMO/Connection.
References: CDS Data Model Views – ABAP Keyword Documentation, DATA – ABAP Keyword Documentation, Structure Types – ABAP Keyword Documentation

Explanation
Secondary keys are additional keys that can be defined for internal tables to optimize the access to the table using fields that are not part of the primary key. Secondary keys can be either sorted or hashed, depending on the table type and the uniqueness of the key. Secondary keys have the following characteristics1:
A). Secondary keys must be chosen explicitly when you actually read from an internal table. This means that when you use a READ TABLE or a LOOP AT statement to access an internal table, you have to specify the secondary key that you want to use with the USING KEY addition. For example, the following statement reads an internal table itab using a secondary key sec_key:
READ TABLE itab USING KEY sec_key INTO DATA(wa).
If you do not specify the secondary key, the system will use the primary key by default2.
B). Multiple secondary keys are allowed for any kind of internal table. This means that you can define more than one secondary key for an internal table, regardless of the table type. For example, the following statement defines an internal table itab with two secondary keys sec_key_1 and sec_key_2:
DATA itab TYPE SORTED TABLE OF ty_itab WITH NON-UNIQUE KEY sec_key_1 COMPONENTS field1 field2 sec_key_2 COMPONENTS field3 field4.
You can then choose which secondary key to use when you access the internal table1.
D). Sorted secondary keys do NOT have to be unique. This means that you can define a sorted secondary key for an internal table that allows duplicate values for the key fields. A sorted secondary key maintains a predefined sorting order for the internal table, which is defined by the key fields in the order in which they are specified. For example, the following statement defines a sorted secondary key sec_key for an internal table itab that sorts the table by field1 in ascending order and field2 in descending order:
DATA itab TYPE STANDARD TABLE OF ty_itab WITH NON-UNIQUE SORTED KEY sec_key COMPONENTS field1 ASCENDING field2 DESCENDING.
You can then access the internal table using the sorted secondary key with a binary search algorithm, which is faster than a linear search3.
The following are not characteristics of secondary keys for internal tables, because:
C). Hashed secondary keys do NOT have to be unique. This is false because hashed secondary keys must be unique. This means that you can only define a hashed secondary key for an internal table that does not allow duplicate values for the key fields. A hashed secondary key does not have a predefined sorting order for the internal table, but uses a hash algorithm to store and access the table rows. For example, the following statement defines a hashed secondary key sec_key for an internal table itab that hashes the table by field1 and field2:
DATA itab TYPE STANDARD TABLE OF ty_itab WITH UNIQUE HASHED KEY sec_key COMPONENTS field1 field2.
You can then access the internal table using the hashed secondary key with a direct access algorithm, which is very fast.
E). Secondary keys can only be created for standard tables. This is false because secondary keys can be created for any kind of internal table, such as standard tables, sorted tables, and hashed tables. However, the type of the secondary key depends on the type of the internal table. For example, a standard table can have sorted or hashed secondary keys, a sorted table can have sorted secondary keys, and a hashed table can have hashed secondary keys1.
References: 1: Secondary Table Key – ABAP Keyword Documentation 2: READ TABLE – ABAP Keyword Documentation 3: Sorted Tables – ABAP Keyword Documentation : Hashed Tables – ABAP Keyword Documentation

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.

The <source> clause in the CDS View Entity Data Definition can be used to specify the data source for the view entity. The <source> clause can accept different types of data sources, depending on the type of the view entity1.
A database table from the ABAP Dictionary: This is a valid type of data source for a CDS View Entity Data Definition. A database table from the ABAP Dictionary is a table that is defined in the ABAP Dictionary using the keyword TABLE or TABLE OF. The name of the database table must be unique within its namespace and must not contain any special characters2.
A CDS DDIC-based view: This is also a valid type of data source for a CDS View Entity Data Definition. A CDS DDIC-based view is a view that is defined in the Core Data Services using the keyword DEFINE VIEW ENTITY. The name of the CDS DDIC-based view must be unique within its namespace and must not contain any special characters3.
You cannot do any of the following:
An external view from the ABAP Dictionary: This is not a valid type of data source for a CDS View Entity Data Definition. An external view from the ABAP Dictionary is a view that is defined in an external application using any language supported by SAP, such as SQL, PL/SQL, or Java. The name of the external view must be unique within its namespace and must not contain any special characters4.
A database view from the ABAP Dictionary: This is not a valid type of data source for a CDS View Entity Data Definition. A database view from the ABAP Dictionary is a view that is defined in an external application using any language supported by SAP, such as SQL, PL/SQL, or Java. The name of the database view must be unique within its namespace and must not contain any special characters4.

Explanation
Core Data Services (CDS) is a framework for defining and consuming semantically rich data models in SAP HANA. CDS supports various features that enhance the capabilities of SQL and enable developers to create data models that are optimized for performance, readability, and extensibility12. Some of the features of CDS are:
Associations: Associations are a way of defining relationships between CDS entities, such as tables or views. Associations enable navigation and path expressions in CDS queries, which allow accessing data from related entities without explicit joins. Associations also support cardinality, referential constraints, and cascading options34.
Annotations: Annotations are a way of adding metadata to CDS entities or their elements, such as fields or parameters. Annotations provide additionalinformation or instructions for the CDS compiler, the database, or the consumers of the CDS views. Annotations can be used for various purposes, such as defining access control, UI rendering, OData exposure, or search capabilities5 .
Structured Query Language (SQL): SQL is the standard language for querying and manipulating data in relational databases. CDS is based on SQL and extends it with additional features and syntax. CDS supports SQL features such as joins, aggregations, filters, expressions, functions, and subqueries. CDS also supports SQL Script, which is a scripting language for stored procedures and functions in SAP HANA .
You cannot do any of the following:
Inheritance: Inheritance is not a feature of CDS. Inheritance is a concept in object-oriented programming that allows a class to inherit the properties and methods of another class. CDS does not support object-oriented programming or classes.
Delegation: Delegation is not a feature of CDS. Delegation is a concept in object-oriented programming that allows an object to delegate some of its responsibilities to another object. CDS does not support object-oriented programming or objects.
References: 1: Core Data Services (CDS) | CAPire 2: Core Data Services [CDS] in SAP S/4 HANA | SAP Blogs 3: Associations in Core Data Services (CDS) | SAP Help Portal 4: [CDS DDL – Association – ABAP Keyword Documentation – SAP Online Help] 5: [Annotations in Core Data Services (CDS) | SAP Help Portal]
[CDS DDL – Annotation – ABAP Keyword Documentation – SAP Online Help] : [Structured Query Language (SQL) | SAP Help Portal] : [CDS DDL – SQL Features – ABAP Keyword Documentation – SAP Online Help] : [Object-Oriented Programming in ABAP | SAP Help Portal]

The RESTful Application Programming feature that is used to ensure the uniqueness of a semantic key is determination. A determination is a type of behavior implementation that defines a logic that is executed automatically when certain events occur, such as create, update, delete, or activate. A determination can be used to calculate or derive values for certain fields, such as semantic keys, based on other fields or external sources. A determination can also be used to check the uniqueness of a semantic key by comparing it with the existing values in the database or the transaction buffer. A determination can use the ABAP SQL or the EML syntax to access and manipulate data. A determination can be defined using the DETERMINE action clause in the behavior definition of a CDS view entity or a projection view. A determination can also be annotated with the @ObjectModel.determination annotation to specify the event, the timing, and the scope of the determination12 The other RESTful Application Programming features are not used to ensure the uniqueness of a semantic key, but have different purposes and effects. These features are:
Validation: A validation is a type of behavior implementation that defines a logic that is executed automatically when certain events occur, such as create, update, delete, or activate. A validation can be used to check the consistency and correctness of the data, such as mandatory fields, data types, value ranges, or business rules. A validation can use the ABAP SQL or the EML syntax to access and manipulate data. A validation can be defined using the VALIDATE action clause in the behavior definition of a CDS view entity or a projection view. A validation can also be annotated with the @ObjectModel.validation annotation to specify the event, the timing, and the scope of the validation12 Action: An action is a type of behavior implementation that defines a logic that is executed explicitly by the user or the application. An action can be used to perform a specific business operation, such as creating, updating, deleting, or activating an entity instance, or triggering a workflow or a notification. An action can use the ABAP SQL or the EML syntax to access and manipulate data. An action can be defined using the ACTION clause in the behavior definition of a CDS view entity or a projection view. An action can also be annotated with the @ObjectModel.action annotation to specify the name, the description, the parameters, and the visibility of the action12

The data declarations that will always work without truncation or rounding for the assignment gv_target = gv_source are B and C. This is because the target data type string is a variable-length character type that can hold any character string, including those of data types c (fixed-length character) and d (date). The assignment of a character or date value to a string variable will not cause any loss of information or precision, as the string variable will adjust its length to match the source value12.
You cannot do any of the following:
A) DATA gv_source TYPE string, to DATA gv_target TYPE c.: This data declaration may cause truncation for the assignment gv_target = gv_source. This is because the target data type c is a fixed-length character type that has a predefined length. If the source value of type string is longer than the target length of type c, the source value will be truncated on the right to fit the target length12.
D) DATA gv_source TYPE p LENGTH 8 DECIMALS 3. to DATA gv_target TYPE p LENGTH 16 DECIMALS 2.: This data declaration may cause rounding for the assignment gv_target = gv_source. This is because the target data type p is a packed decimal type that has a predefined length and number of decimal places. If the source value of type p has more decimal places than the target type p, the source value will be rounded to the target number of decimal places12.

The following are the explanations for each statement:
C: This statement is valid. Class CL1 uses the interface. This is because class CL1 implements the interface ifl using the INTERFACES statement in the public section of the class definition. The INTERFACES statement makes the class compatible with the interface and inherits all the components of the interface. The class can then use the interface components, such as the method ml, by using the interface component selector ~, such as ifl~ml12 E: This statement is valid. Class CL1 implements the interface. This is because class CL1 implements the interface ifl using the INTERFACES statement in the public section of the class definition. The INTERFACES statement makes the class compatible with the interface and inherits all the components of the interface. The class must then provide an implementation for the interface method ml in the implementation part of the class, unless the method is declared as optional or abstract12 D: This statement is valid. In class CL2, the interface method is named ifl~ml. This is because class CL2 has a data member named m0_ifl of type REF TO ifl, which is a reference to the interface ifl. The interface ifl defines a method ml, which can be called using the reference variable m0_ifl. The interface method ml has the name ifl~ml in the class, where ifl is the name of the interface and the character ~ is the interface component selector12 The other statements are not valid, as they have syntax errors or logical errors. These statements are:
A: This statement is not valid. In class CL1, the interface method is named ifl~ml, not if-ml. This is because class CL1 implements the interface ifl using the INTERFACES statement in the public section of the class definition. The interface ifl defines a method ml, which can be called using the class name or a reference to the class. The interface method ml has the name ifl~ml in the class, where ifl is the name of the interface and the character ~ is the interface component selector. Using the character – instead of the character ~ will cause a syntax error12 B: This statement is not valid. Class CL2 does not use the interface, but only has a reference to the interface. This is because class CL2 has a data member named m0_ifl of type REF TO ifl, which is a reference to the interface ifl. The interface ifl defines a method ml, which can be called using the reference variable m0_ifl. However, class CL2 does not implement the interface ifl, nor does it inherit the interface components. Therefore, class CL2 does not use the interface, but only references the interface12

The field4 is defined incorrectly in the ABAP code snippet. The reason is that the data type c (character) cannot have a decimal places specification. The decimal places specification is only valid for the data types p (packed number) and f (floating point number)1. Therefore, the field4 definition should either omit the decimal places specification or change the data type to p or f.

Core Data Services (CDS) is a framework for defining and consuming semantically rich data models in SAP HANA. CDS supports various features that enhance the capabilities of SQL and enable developers to create data models that are optimized for performance, readability, and extensibility12. Some of the features of CDS are:
Associations: Associations are a way of defining relationships between CDS entities, such as tables or views. Associations enable navigation and path expressions in CDS queries, which allow accessing data from related entities without explicit joins. Associations also support cardinality, referential constraints, and cascading options34.
Annotations: Annotations are a way of adding metadata to CDS entities or their elements, such as fields or parameters. Annotations provide additional information or instructions for the CDS compiler, the database, or the consumers of the CDS views. Annotations can be used for various purposes, such as defining access control, UI rendering, OData exposure, or search capabilities5 .
Structured Query Language (SQL): SQL is the standard language for querying and manipulating data in relational databases. CDS is based on SQL and extends it with additional features and syntax. CDS supports SQL features such as joins, aggregations, filters, expressions, functions, and subqueries. CDS also supports SQL Script, which is a scripting language for stored procedures and functions in SAP HANA .
You cannot do any of the following:
Inheritance: Inheritance is not a feature of CDS. Inheritance is a concept in object-oriented programming that allows a class to inherit the properties and methods of another class. CDS does not support object-oriented programming or classes.
Delegation: Delegation is not a feature of CDS. Delegation is a concept in object-oriented programming that allows an object to delegate some of its responsibilities to another object. CDS does not support object-oriented programming or objects.

Explanation
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

Explanation
When accessing the subclass instance through go_super, you can do both of the following:
Access the inherited private components: A subclass inherits all the private attributes and methods of its superclass, unless they are explicitly overridden by the subclass. Therefore, you can access the inherited private componentsof the superclass through go_super, as long as they are not hidden by other attributes or methods in the subclass12.
Access the inherited public components: A subclass inherits all the public attributes and methods of its superclass, unless they are explicitly overridden by the subclass. Therefore, you can access the inherited public components of the superclass through go_super, as long as they are not hidden by other attributes or methods in the subclass12.
You cannot do any of the following:
Call a subclass specific public method: A subclass does not have any public methods that are not inherited from its superclass. Therefore, you cannot call a subclass specific public method through go_super12.
Call inherited public redefined methods: A subclass does not have any public methods that are redefined from its superclass. Therefore, you cannot call inherited public redefined methods through go_super12.
References: 1: Object Oriented – ABAP Development – Support Wiki 2: Inheritance and Instantiation – ABAP Keyword Documentation

A metadata extension is a RESTful Application Programming object that can be used to organize the display of fields in an app. A metadata extension is a CDS view that annotates another CDS view with UI annotations, such as labels, icons, or facets. These annotations define how the data should be presented in the app, such as which fields should be shown on the object page, which fields should be editable, or which fields should be used for filtering or sorting. A metadata extension can also be used to add custom actions or validations to the app12. Reference: 1: Refine the Object Page with Annotations | SAP Tutorials 2: ABAP RAP : Enabling custom actions with a dialog for additional input fields | SAP Blogs

Explanation
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

ABAP SQL arithmetic expressions have different restrictions depending on the data type of the operands. The following are some of the restrictions:
Floating point types and integer types can be used in the same expression, as long as the integer types are cast to floating point types using the cast function. For example, CAST ( num1 AS FLTP ) / CAST ( num2 AS FLTP ) is a valid expression, where num1 and num2 are integer types.
The operator / is allowed only in floating point expressions, where both operands have the type FLTP or f. For example, num1 / num2 is a valid expression, where num1 and num2 are floating point types. If the operator / is used in an integer expression or a decimal expression, a syntax error occurs.
Decimal types and integer types can be used in the same expression, as long as the expression is a decimal expression. A decimal expression has at least one operand with the type DEC, CURR, or QUAN or p with decimal places. For example, num1 + num2 is a valid expression, where num1 is a decimal type and num2 is an integer type.
The operator ** is allowed only in floating point expressions, where both operands have the type FLTP or f. For example, num1 ** num2 is a valid expression, where num1 and num2 are floating point types. If the operator ** is used in an integer expression or a decimal expression, a syntax error occurs.