SQlite3 和 python 中的日期时间对象

Question

Trying to store datetimes in my database project using python and sqlite3. Here's what I have so far...

import sqlite3

def connect():
    conn = sqlite3.connect("road_works.db")
    cur = conn.cursor()
    cur.execute("""CREATE TABLE IF NOT EXISTS road_works(id INTEGER PRIMARY 
        KEY, location TEXT, client TEXT, start_date TEXT, end_date TEXT)""")
    conn.commit()
    conn.close()


def insert(location, client, start_date, end_date):
    conn = sqlite3.connect("road_works.db")
    cur = conn.cursor()
    cur.execute("INSERT INTO road_works VALUES (NULL, ?, ?, ?, ?)",
               (location, client, start_date, end_date))
    conn.commit()
    conn.close()

insert("M25", "Lindor", "2019-03-16 20:00", "2019-07-16 06:00")

At the minute the database takes start_date and end_date as text. I want to change that to dates that I can then start doing calculations with like counting down the days/nights until the job is finished etc. The user will also be inputing the dates and times so I cant use datetime.datetime.now()/today() I have been reading into datetime but its more advanced than I'm used to if anyone could explain it better I would appreciate it.

I have been searching for the solution for a few days this is my first project it may be a little out of my league but I appreciate your attention.

Thanks :)

fixed! Thanks for the help!

def insert(location, client, start_date, end_date):
    conn = sqlite3.connect("road_works.db")
    cur = conn.cursor()
    cur.execute("INSERT INTO road_works VALUES (NULL, ?, ?, ?, ?)",
                (location, client, start_date, end_date))
    start_date = datetime.strptime(start_date, "%Y-%m-%d %H:%M")
    end_date = datetime.strptime(end_date, "%Y-%m-%d %H:%M")
    conn.commit()
    conn.close()

Answer 1

There is no native datatype for dates in sqlite. The manual that I link to advises (see 2.2) three possible ways to store a date:

• TEXT (ISO 8601 string)
• REAL (Julian day numbers)
• INTEGER (Unix Time)

My suggestion would be to use ISO 8601 format, since it is standardized and unambiguous. Additionally, as opposed to the alternatives it is human-readable without conversion. And datetime objects have standard conversion methods to and from a string for it.

See examples below:

In [1]: from datetime import datetime                                                                    

In [2]: now = datetime.now()                                                                             

In [3]: now                                                                                              
Out[3]: datetime.datetime(2019, 1, 3, 14, 53, 38, 596477)

In [4]: string = now.isoformat()                                                                         

In [5]: string                                                                                           
Out[5]: '2019-01-03T14:53:38.596477'

In [6]: datetime.fromisoformat(string)                                                                   
Out[6]: datetime.datetime(2019, 1, 3, 14, 53, 38, 596477)

Answer 2

You can use datetime.strtime to convert a string to datetime object

eg

from datetime import datetime
datetime_object = datetime.strptime('2019-03-16 20:00', '%Y-%m-%d %H:%M')

SO