pub fn are_primary_columns(&self, column_names: &Vec<String>) -> bool {
        for c in column_names {
            if !self.is_primary(&c) {
                return false;
            }
        }
        true
    }
/// return true when all columns are primary columns
/// false if at least 1 is not a primary column
return true when all columns are primary columns
false if at least 1 is not a primary column
return true when all columns are primary columns false if at least 1 is not a primary column
pub fn are_primary_columns(&self, column_names: &Vec<String>) -> bool {
        for c in column_names {
            if !self.is_primary(&c) {
                return false;
            }
        }
        true
    }
pub fn are_primary_columns ( & self , column_names : & Vec < String > ) -> bool { for c in column_names { if ! self . is_primary ( & c ) { return false ; } } true }
return true when all columns are primary columns
false if at least 1 is not a primary column
return true when all columns are primary columns false if at least 1 is not a primary column
&self
column_names
&Vec<String>
&self
column_names
&Vec<String>