Conversion Functions in ABAP CDS View Entities

Conversion functions are among the most powerful built-in functions available in ABAP CDS View Entities. They allow developers to safely convert business semantic values such as currencies, quantities, units, and amounts into formats suitable for calculations, reporting, and analytics.

One of the most common mistakes made by developers transitioning from classical ABAP to ABAP Cloud is assuming that business semantic types such as CURR and QUAN behave like ordinary numeric values. In reality, these data types carry business meaning that SAP protects during CDS processing.

Instead of relying on implicit conversions, ABAP CDS provides a rich collection of conversion functions that execute directly inside SAP HANA while preserving the business semantics defined in the Virtual Data Model (VDM).

By the end of this lesson, you will understand when each conversion function should be used and how to avoid the most common mistakes encountered during CDS development.

To understand conversion functions, we first need to understand the difference between a technical numeric value and a business semantic value.

Consider a billing document amount stored as a CURR field. Although it looks like a decimal number, it actually consists of two pieces of information:

• The numeric amount.
• The associated currency key.

Removing either piece of information changes the business meaning of the value.

This distinction is the primary reason why conversion functions exist. SAP intentionally separates business semantics from technical numeric calculations to ensure financial and logistical accuracy.

One of the most common activation errors in ABAP CDS occurs when developers attempt to perform arithmetic operations directly on CURR or QUAN fields.

Since these fields contain business semantics in addition to their numeric value, CDS does not treat them as ordinary decimal numbers. The GET_NUMERIC_VALUE() function removes those semantics and returns only the underlying numeric value, making it suitable for calculations.

get_numeric_value( amount_or_quantity )

Consider the following billing amount.

TotalNetAmount * 0.18 as GSTAmount

Depending on the data type, this expression may fail to activate because TotalNetAmount is a CURR field rather than a simple decimal value.

Instead, remove the currency semantics first.

get_numeric_value(
    TotalNetAmount
) * 0.18 as GSTAmount

Although GET_NUMERIC_VALUE() removes business semantics, many financial calculations require higher decimal precision than standard packed numbers.

This is where CURR_TO_DECFLOAT_AMOUNT()becomes useful.

curr_to_decfloat_amount( amount )

Instead of simply removing the business semantics, this function converts a CURR field into a DECFLOAT34 value suitable for high-precision financial calculations.

curr_to_decfloat_amount(
    TotalNetAmount
) * 1.18 as GrossAmount

The resulting value has the DECFLOAT type, making it ideal for calculations that require greater decimal precision than packed numbers.

The CURRENCY_CONVERSION() function converts an amount from one currency into another using the exchange rates maintained in the SAP system.

Unlike GET_NUMERIC_VALUE() or CURR_TO_DECFLOAT_AMOUNT(), this function performs a true business conversion rather than simply changing the technical data type.

currency_conversion(
    amount               => amount,
    source_currency      => source_currency,
    target_currency      => target_currency,
    exchange_rate_date   => exchange_rate_date
)

@Semantics.amount.currencyCode: 'TransactionCurrency'

currency_conversion(

    amount               => TotalNetAmount,

    source_currency      => TransactionCurrency,

    target_currency      => cast( 'USD' as abap.cuky(5) ),

    exchange_rate_date   => $session.system_date

) as USDAmount

SAP automatically determines the exchange rate using the configured exchange rate tables and converts the billing amount into USD.

One of the most common activation errors looks like this:

Literal of type CHAR is not supported for parameter TARGET_CURRENCY

Many developers naturally write:

target_currency => 'USD'

However, the target_currency parameter expects a value of type CUKY, not a plain character literal.

target_currency => cast(
    'USD'
    as abap.cuky(5)
)

Another common question is:

What happens if SAP cannot determine an exchange rate?

By default, CDS raises an exception and the query fails.

To control this behavior, use the error_handling parameter.

Just as CURRENCY_CONVERSION() converts monetary values between different currencies, UNIT_CONVERSION() converts quantities between different units of measure using the conversion rules maintained in SAP.

Instead of manually multiplying values by conversion factors, SAP automatically determines the correct conversion ratio based on the configured Unit of Measure (UoM) master data.

unit_conversion(

    quantity        => quantity,

    source_unit     => source_unit,

    target_unit     => target_unit

)

@Semantics.quantity.unitOfMeasure: 'BaseUnit'

unit_conversion(

    quantity        => OrderQuantity,

    source_unit     => BaseUnit,

    target_unit     => cast(
        'KG'
        as abap.unit(3)
    )

) as QuantityInKG

SAP automatically converts the quantity into kilograms using the maintained Unit of Measure conversion definitions.

Just like currency conversion, the target_unit parameter expects the semantic data type UNIT, not a character literal.

target_unit => 'KG'

target_unit => cast(

    'KG'

    as abap.unit(3)

)

UNIT_CONVERSION() supports the same error handling strategies as CURRENCY_CONVERSION().

unit_conversion(

    quantity        => OrderQuantity,

    source_unit     => BaseUnit,

    target_unit     => cast(
        'KG'
        as abap.unit(3)
    ),

    error_handling  => 'SET_TO_NULL'

) as QuantityInKG

Both CURRENCY_CONVERSION() and UNIT_CONVERSION() perform business conversions using SAP configuration.

In production systems, conversions may occasionally fail because exchange rates or unit conversion definitions are unavailable. Instead of allowing the entire CDS query to fail, SAP provides the error_handling parameter to control the desired behavior.

In the accompanying video, we'll implement every conversion function discussed in this lesson using Eclipse ADT and SAP S/4HANA Public Cloud. We'll troubleshoot common activation errors, explore error handling strategies, and build production-ready examples.