Error in Process model

Question

Hi All for the attached code it is showing the error attached. The attached code will saved into "Country " variable Of type textCould you please help me rule!ISR_er_displayCountryNameById(
 countryId: index(
 rule!ISR_qry_GetAddressInfo(
 type: cons!ISR_REF_CODE_ADDRESS_TYPE_PRIMARY_RESEARCHER,
 typeId: index(
 rule!ISR_qry_GetPersonDetailsbyStudyRequestId(
 studyRequestId: pv!studyRequest.studyRequestId,
 
 ).data,
 "studyPnId",
 null
 )
 ).data,
 "countryId",
 {}
 )
)

Mathieu Drouin · Answer

One of the queries is returning a null and .data is not resolving to anything. 
 You can either fix the queries to force it to return a datasubset (even if empty) or you can check for nulls in this expression and adjust behaviour accordingly. 
 That being said, nesting queries like this is not a best practice. With Record Types (with the appropriate relations), this type of query would be much cleaner.

Harshit Bumb (Appyzie) · Answer

The error itself is very clear. When you have already used index() function, why not put the data in it too?