Passing a datetime into psycopg2

Question

I am trying to insert a datetime value into my postgres database using Psycopg2.

My code was working before, but I switched from %s notation to {} notation, and my code broke.

here is my code

for j in eveLists.itemList:
    tempPrice = fetchSellPrice(i, j)
    database_name = eveLists.DatabaseDict[i]
    now = datetime.datetime.utcnow()

    cur.execute("INSERT INTO {0} VALUES ({1}, {2}, {3}, NULL, {4}, {5}, NULL);".format(
                                                                                       database_name,
                                                                                       str(i),
                                                                                       str(j),
                                                                                       float(tempPrice),
                                                                                       datetime.date.today(),
                                                                                       now))

I get the following error:

psycopg2.ProgrammingError: syntax error at or near "00"
LINE 1: ...0000142, 2268, 3.11, NULL, 2017-05-09, 2017-05-10 00:40:03.3...
                                                             ^

It is treating the date and the time as two separate objects.

I have tried several different ways which are commented out, and all throw various error messages. I have tried wrapping the datetime in quotes,

now = ("'%s'") % str(datetime.datetime.utcnow())

which give an error

psycopg2.ProgrammingError: column "mydate" is of type date but expression is of type integer
LINE 1: ...NTO temp_jita VALUES (30000142, 2268, 3.11, NULL, 2017-05-09...
                                                             ^
HINT:  You will need to rewrite or cast the expression.

It thinks my date is an integer, even though I wrapped it in quotes.

I have also tried making a psycopg2 timestamp manually:

now = psycopg2.Timestamp(now.strftime("%Y"),
                                     now.strftime("%m"),
                                     now.strftime("%d"),
                                     now.strftime("%h"),
                                     now.strftime("%M"),
                                     int(now.strftime("%-S")))

Which gives the following error:

    int(now.strftime("%-S")))
TypeError: an integer is required (got type str)

I don't know how it thinks this is a string, especially since I cast it as an int!

Any help would be appreciated.

EDIT: The reason I passed the variables using {} notation and not %s notation is because I received an error for the following code:

  for j in eveLists.itemList:
            tempPrice = fetchSellPrice(i, j)
            database_name = eveLists.DatabaseDict[i]
            now = datetime.datetime.utcnow()
            now = str(now)

            cur.execute("INSERT INTO %s VALUES (%s, %s, %s, NULL, %s, %s, NULL);", [database_name,
                                                                                    str(i),
                                                                                    str(j),
                                                                                    float(tempPrice),
                                                                                    datetime.date.today(),
                                                                                    now
                                                                                    ])

psycopg2.ProgrammingError: syntax error at or near "'temp_jita'"
LINE 1: INSERT INTO 'temp_jita' VALUES ('30000142', '2268', 3.03, NU...
                    ^

Please refer to my previous post on the subject: How to remove the quotes from a string for SQL query in Python?

EDIT: following @Zorg 's advice from this link (https://www.psycopg.org/docs/usage.html), this code worked for me:

cur.execute(sql.SQL("INSERT INTO {} VALUES (%s, %s, %s, NULL, %s, %s, NULL);").format(sql.Identifier(database_name)),[
                                                                                    str(i),
                                                                                    str(j),
                                                                                    float(tempPrice),
                                                                                    datetime.date.today(),
                                                                                    now
                                                                                    ])

Answer 1

Have you read "Psycopg2 usage"?

If not, don't hesitate to do so.

Warning NEVER, NEVER, NEVER use Python string concatenation (+) or string parameters interpolation (%) to pass variables to a SQL query string. Not even at gunpoint.

Proper way of passing params into a query is shown below:

 SQL = "INSERT INTO authors (name) VALUES (%s);" # Note: no quotes
 data = ("O'Reilly", )
 cur.execute(SQL, data) # Note: no % operator

Answer 2

AsIs andquote_ident

from psycopg2.extensions import AsIs, quote_ident

cur.execute("""
    INSERT INTO %s
    VALUES (%s, %s, %s, NULL, %s, %s, NULL);
""", (
    AsIs(quote_ident(database_name, cur)),
    str(i),
    str(j),
    float(tempPrice),
    datetime.date.today(),
    now
))