How to set a calculated field from a stored procedure in a transient field of Entity?

There is a table in the database (Firebird), it is mapped to Entity.

A stored procedure works with this table, which returns both the field values from the table and the calculated value.

For this calculated value in Entity, I created a Transient variable.

I have SqlResultSetMapping in which I wrote the correspondence of fields from the stored procedure to the fields in Entity.

The problem is that nothing is written to the Transient field.

Is it possible to set calculated value to transient field?

@NamedStoredProcedureQuery(
        name = Building.VR,
        procedureName = "VALUATION_RESULTS_VC",
        resultSetMappings = "Mapping",
        parameters = {
            @StoredProcedureParameter(mode = ParameterMode.IN, name = "IP_ID", type = Integer.class),
            @StoredProcedureParameter(mode = ParameterMode.OUT, name = "P_ID", type = Integer.class),
            @StoredProcedureParameter(mode = ParameterMode.OUT, name = "P_CLASS", type = String.class),
            @StoredProcedureParameter(mode = ParameterMode.OUT, name = "P_CRN_VC", type = Double.class)
        }
)
@SqlResultSetMapping(
        name = "Mapping",
        entities = @EntityResult(
                entityClass = Building.class,
                fields = {
                        @FieldResult(name = "id", column = "P_ID"),
                        @FieldResult(name = "name", column = "P_CLASS"),
                        @FieldResult(name = "crn", column = "P_CRN_VC")
                }
                )
)
@Access(AccessType.FIELD)
@Entity
@Table(name = "main_tab")
public class Building extends BaseEntity {
    public static final String VR = "Asset.VR";

    @Transient <-if you remove Transient and create such a real field in the table, then everything works. But this field is calculated and it is not needed in the table.
    private Double crn;

    public Double getCrn() {
        return crn;
    }

    public void setCrn(Double crn) {
        this.crn = crn;
    }
}



@MappedSuperclass
public abstract class BaseEntity {
    @Id
    @Column(name = "id")
    private Integer id;

    @Column(name = "name")
    private String name;

    public Integer getId() {
        return id;
    }

    public String getName() {
        return name;
    }
}

I found one alternative solution like:

In entity class, define property with @column(update=false,insertable=false) which still creates a column in table but acts a read only column. Use this column for derived column to fetch from stored procedure.