parameter unsupported when inserting int in sqlite

问题:

I have been going around and around with storing date and time in SQLite3 with the intention of retrieving the records using comparisons later e.g. SELECT * WHERE date1 < date2

I finally gave up trying to store datetime.datetime objects and decided to use a UNIX timestamp instead as they are just an int and easy to manipulate but I am still getting errors.

import sqlite3 as lite
import datetime
import time

conn = lite.connect('dispatcher.db')
cur = conn.cursor()
query = "create table if not exists new_test (curent_dt)"
cur.execute(query)
conn.commit()
now = datetime.datetime.now() - datetime.timedelta(minutes=60)
temp = int(time.mktime(now.timetuple()))
cur.execute('insert into new_test (curent_dt) values (? )', (temp))
conn.commit()
conn.close()

returns the following error:

cur.execute('insert into new_test (curent_dt) values (? )', (temp)) ValueError: parameters are of unsupported type

After investigating the problem a little further I found that you have to use a trailing comma to create a single element tuple e.g. (temp,)

回答1:

Note the added comma after "temp" below:

cur.execute('insert into new_test (curent_dt) values (?)', (temp,))

The reason this happens is that (temp) is an integer but (temp,) is a tuple of length one containing temp.

回答2:

cur.execute('insert into new_test (curent_dt) values (? )', (temp))

Replace this code with

cur.execute('insert into new_test (curent_dt) values (? )', (temp,))

In Python, (temp) and (temp,) are two different things. (temp) is just a normal variable like integer but (temp,) is a tuple. Tuple is only taken by providing commas after each element and the execute() method takes only tuples in its second parameter.

回答3:

changing that line with this

cur.execute('insert into new_test (curent_dt) values (?)',str(temp))