A python module storing some common functions about sqlite

sqlitehandler.py

import sqlite3
import pandas as pd
import functools as ft

class SqliteHandler:
    def __init__(self, dbname):
        self.dbname = dbname

    def df2table(self, tablename, df):
        # connect to db
        conn = sqlite3.connect(self.dbname)
        cur = conn.cursor()

        # define columns
        cols = list(df.columns)

        cols_str = ft.reduce(lambda x,y: x+','+y, cols)
        qmarks_str = ft.reduce(lambda x,y: x+','+y, ['?']*len(cols))

        # create table if not exists
        cur.execute("CREATE TABLE IF NOT EXISTS "+tablename+" ("+cols_str+");")

        # format data to insert to db
        to_db = []
        for index, row in df.iterrows():
            y = tuple(map(lambda x: row[x], cols))
            to_db.append(y)

        # insert data
        cur.executemany("INSERT INTO "+tablename+" ("+cols_str+") VALUES ("+qmarks_str+");", to_db)
        conn.commit()

        # close db connection
        conn.close()

    def table2df(self, query):
        # make a connection
        conn = sqlite3.connect(self.dbname)
        cur = conn.cursor()
        # execute query
        cur.execute(query)
        l = cur.fetchall()
        # close the connection
        cur.close()
        # convert to data frame
        return pd.DataFrame(l) # no column name tho

    def columns(self, tablename):
        # make a connection
        conn = sqlite3.connect(self.dbname)
        cur = conn.cursor()
        # get column names
        cur.execute( "PRAGMA table_info("+tablename+")")
        h = cur.fetchall()
        return list(map(lambda x: x[1], h)) # formatting