SQLiteDB from file to memory and back to file

SQLiteToMemory.py

#!/usr/bin/env python3

#
# SQLiteToMemory
# Python class to load sqlite3 database to memory and back to file
# Written by Maximilian Thoma 2019
# Version 0.1
#

import sqlite3
from io import StringIO
import shutil


class SQLiteToMemory:

    def __init__(self, file):
        self.file = file
        self.new_file = file + "_NEW"
        self.con_file = sqlite3.connect(self.file)
        self.con_new_file = sqlite3.connect(self.new_file)
        self.con_memory = sqlite3.connect(":memory:")
        self.tmp_file = StringIO()
        self.tmp_memory = StringIO()

    def load_to_memory(self):
        # Load database from file to memory
        for line in self.con_file.iterdump():
            self.tmp_file.write('%s\n' % line)
        self.tmp_file.seek(0)
        self.con_memory.cursor().executescript(self.tmp_file.read())
        self.con_memory.commit()

    def dump_to_file(self):
        # Dump memory database back to file
        for line in self.con_memory.iterdump():
            self.tmp_memory.write('%s\n' % line)
        self.tmp_memory.seek(0)
        self.con_new_file.cursor().executescript(self.tmp_memory.read())
        self.con_new_file.commit()
        self.con_new_file.close()
        self.con_memory.close()
        shutil.move(self.new_file, self.file)

    def con_memory(self):
        # Returns connection to memory database
        return self.con_memory

########################################################################################################
# Example:

db = SQLiteToMemory("test.db")
db.load_to_memory()

cursor = db.con_memory.cursor()
cursor.execute("SELECT * FROM testtable")
rows = cursor.fetchall()
print(len(rows))
cursor.execute("INSERT INTO testtable VALUES(NULL, 'TEST1','TEST1',NULL,'TEST1')")
db.dump_to_file()

########################################################################################################