ABAP CDS Input Parameter - Force Mandatory Value

[sap_cohort]

Hi, I have an ABAP CDS Query with a two parameters.  

1. The first parameter the user can dropdown to select the appropriate value.
2. The second parameter I am defaulting a single value and want to restrict the parameter to this value.
   I would like to restrict the parameter so the user cannot use any value other than the defaulted value.
   They can attempt to change the value, but any other value should be an input error for that parameter.
   I could hide the defaulted parameter, but I want it to show on the selection screen for added context.
   I'd like to somehow make sure it's apparent to the user that this defaulted value is the only value allowed for the input parameter.  

Is there any way possible to restrict an ABAP CDS Input Parameter to single specific value as mentioned above?   

Thanks for any input on this. 

[sap_cohort]

Hi, I have an ABAP CDS Query with a two parameters.  

1. The first parameter the user can dropdown to select the appropriate value.
2. The second parameter I am defaulting a single value and want to restrict the parameter to this value.
   I would like to restrict the parameter so the user cannot use any value other than the defaulted value.
   They can attempt to change the value, but any other value should be an input error for that parameter.
   I could hide the defaulted parameter, but I want it to show on the selection screen for added context.
   I'd like to somehow make sure it's apparent to the user that this defaulted value is the only value allowed for the input parameter.  

Is there any way possible to restrict an ABAP CDS Input Parameter to single specific value as mentioned above?   

Thanks for any input on this.