code: public static void addMissingColumns(SQLiteDatabase database, Class contractClass) {
  
          Contract contract = new Contract(contractClass);
  
          Cursor cursor = database.rawQuery("PRAGMA table_info(" + contract.getTable() + ")", null);
          for (ContractField field : contract.getFields()) {
              if (!fieldExistAsColumn(field.name, cursor)) {
                  database.execSQL("ALTER TABLE " + contract.getTable() + " ADD COLUMN " + field.name + " " + field.type + ";");
              }
          }
      }
docs: Adds missing table columns for the given contract class.
  
  @param database      The database in which the updated table is.
  @param contractClass The contract class to work with.