Inserting row into Postgresql using python

Question

I created a table in postgreqsl using python and would like to fill it with random dataset containing different data types. But I get the error 'not all arguments converted during string formatting'. Anybody an idea what im doing wrong. I have read through other post but I cant find the solution.

creating table

def create_tables():
""" create table in the PostgreSQL database"""
commands = (
    """
    Create TABLE flight_observations(
            time TIMESTAMP,
            numDayofweek INTEGER,
            numHour INTEGER,
            ac_type TEXT,
            adep TEXT,
            ades TEXT,
            curr_sect TEXT,
            lon_t FLOAT(6),
            lat_t FLOAT(6),
            vg_t INTEGER,
            hdot_t FLOAT8,
            bearing FLOAT8,
            WCA FLOAT8,
            ws FLOAT8,
            wd FLOAT8,
            temp INTEGER
    )
    """)
conn = None
try:
    # connection string
    conn_string = "host='localhost' dbname='postgres' user='postgres' password='xxxx'"
    # print connection string to connect
    print "Connecting to database\n ->%s" % (conn_string)
    # read the connection parameters
    params = Config()
    # connect to the PostgreSQL server
    conn = psycopg2.connect(conn_string)
    cur = conn.cursor()
    # create table one by one

    cur.execute(commands)
    # close communication with the PostgreSQL database server
    cur.close()
    # commit the changes
    conn.commit()
except (Exception, psycopg2.DatabaseError) as error:
    print(error)
finally:
    if conn is not None:
        conn.close()

data

flight_obs = ['2016-07-01 16:42:21', 'A319', 'EDDB', 'EGKK', 'EDYYSOLX', 11.071111, 52.366389, 206.5938752827827, 5.55, 268.9576458923286, 5.238123301016344, 29.257257205897805, 234.0554644610864, 221.8523282183259]

filling table

def insert_flight_list(flight_obs):
sql = "INSERT INTO flight_observations(time, ac_type, adep, ades, curr_sect, lon_t, lat_t, vg_t, hdot_t, bearing, wca, ws, wd, temp) VALUES ( %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)"
conn = None
try:
    # connection string
    conn_string = "host='localhost' dbname='postgres' user='postgres' password='xxxx'"
    # print connection string to connect
    print "Connecting to database\n ->%s" % (conn_string)
    # read database configuration
    params = Config()
    # connect to the PostgreSQL database
    conn = psycopg2.connect(conn_string)
    # create a new cursor
    cur = conn.cursor()
    # execute the INSERT statement
    cur.executemany(sql, flight_obs)
    conn.commit()
    cur.close()
except (Exception, psycopg2.DatabaseError) as error:
    print(error)
finally:
    if conn is not None:
        conn.close()

insert_flight_list(flight_obs)

Not sure why the try statements are not indenting in this post. They are indented in the python code

Which line of your code is giving you this error?

user8098055
– user8098055

2018-01-29 15:48:26 +00:00
Commented Jan 29, 2018 at 15:48 — user8098055
– user8098055, Commented Jan 29, 2018 at 15:48

Community · Accepted Answer · 2020-06-20 09:12:55Z

1

I believe the issue is with cur.executemany(sql, flight_obs). The docs say:

executemany(sql, vars_list)

Execute a database operation (query or command) against all parameter tuples or mappings found in the sequence vars_list.

so it's effectively doing the equivalent of:

for i in flight_obs:
    cur.execute(sql, i)

Since flight_obs is a list of strings, not tuples/mappings, you end up with something like:

cur.execute(sql, '2016-07-01 16:42:21')
cur.execute(sql, 'A319')
cur.execute(sql, 'EDDB')

Simple fix - just replace cur.executemany with cur.execute and it should all work.

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Jan 29, 2018 at 15:56

match

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1 Comment

mastersom Over a year ago

Yes, True. Thanks @match. I just saw it myself right now.

Chris Curvey · Accepted Answer · 2018-01-29 15:57:03Z

0

turn your "flight_obs" into a tuple before passing it to executemany()

cur.executemany(sql, tuple(flight_obs))

BTW, do you want "exeutemany" or just "execute"?

answered Jan 29, 2018 at 15:57

Chris Curvey

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