code: def read(database, table, key):
      
      with database.snapshot() as snapshot:
          result = snapshot.execute_sql('SELECT u.* FROM %s u WHERE u.id="%s"' %
                                        (table, key))
          for row in result:
              key = row[0]
          for i in range(NUM_FIELD):
              field = row[i + 1]
docs: Does a single read operation.