The annotation @Environment.systemField: #SYSTEMLANGUAGE links the CDS view parameter plangu to the ABAP system field sy-langu. This creates an implicit default value. When the CDS view is consumed, either directly in an ABAP SQL statement or as a data source in another CDS view (view-on-view), the system automatically passes the value of sy-langu to the parameter if no explicit value is provided. However, this is only a default mechanism. The consumer of the CDS view can still explicitly pass a different value to the parameter, which will override the automatic system language value.

C. The value of sy-langu will be passed to the CDS view automatically when you use the CDS view in ABAP but not when you use it in another view entity

This is incorrect. The default value mechanism applies in all consumption scenarios, including when the view is used as a data source for another CDS view.

D. It is no longer possible to pass your own value to the parameter.

This is incorrect. The annotation provides a default value, not a restriction. It is always possible to override this default by explicitly passing a value to the parameter.

1. SAP Help Portal

ABAP Keyword Documentation: ABAP CDS - DEFINE VIEW ENTITY

parameterannot.

Section: @Environment.systemField

Content: This section explicitly states

"Specifies a system field of the ABAP environment whose value is passed implicitly to the parameter in an Open SQL read." It further clarifies

"If an explicit actual parameter is specified for an input parameter p... this value is used. Otherwise

the value of the system field specified in the annotation is used." This directly supports that the value is passed automatically (supporting A) and can be overridden (supporting B and refuting D).

2. SAP Help Portal

ABAP Keyword Documentation: ABAP CDS - Parameter Passing.

Section: Parameter Passing from a CDS View

Content: This documentation explains how parameters are handled in view-on-view scenarios. If a consuming view uses a parameterized view

it must handle the parameter. If it doesn't explicitly pass a value

the default mechanism of the underlying view (in this case

the @Environment.systemField annotation) is triggered. This supports option A and refutes option C.