1 import sqlite3
   2 import pprint
   3 from typing import *
   4 
   5 class Database(object):
   6     """A reference to a database."""
   7 
   8     def __init__(
   9         self,
  10         cursor: sqlite3.Cursor,
  11     ) -> None:
  12         self.curs = cursor
  13 
  14     def execute(
  15         self,
  16         cmd: str,
  17         vals: Tuple = tuple(),
  18     ) -> List:
  19         self.curs.execute(cmd, vals)
  20         return self.curs.fetchall()
  21 
  22 
  23 class open_db(object):
  24     """Context manager for sqlite3 DB."""
  25 
  26     def __init__(
  27         self,
  28         filename: str,
  29     ) -> None:
  30         self.conn = sqlite3.connect(filename, detect_types=sqlite3.PARSE_DECLTYPES)
  31         self.curs = self.conn.cursor()
  32 
  33     def __enter__(self) -> sqlite3.Cursor:
  34         return Database(self.curs)
  35 
  36     def __exit__(
  37         self,
  38         *exception: Any,
  39     ) -> None:
  40         self.conn.commit()
  41         self.curs.close()
  42         self.conn.close()
  43 
  44 
  45 with open_db(":memory:") as db:
  46     db.execute("CREATE TABLE mytable (num INTEGER, name TEXT)")
  47     for n in range(10):
  48         db.execute("INSERT INTO mytable (num,name) VALUES (?,?)", (n,str(n)))
  49     data = db.execute("SELECT * FROM mytable")
  50     pprint.pprint(data)