Python sqlite3's executemany function returns ValueError

Question

I have the following python code which is part of a larger for loop, where I am inserting latlon data along with weather data for future inspection. Note that I am checking if the data at that iteration is float64 (since it could also be masked, where I'd rather skip).

values = (lat_db,lon_db,sst_db)
        if type(sst_db) != numpy.float64:
            continue

        c.executemany('INSERT INTO current VALUES(?,?,?)',values)

The table itself was created through these lines:

conn = sqlite3.connect('sst.db')
c = conn.cursor()

# Create the database table.
c.execute('''CREATE TABLE current
             (lat real, lon real, sst real)''')

Upon running my script, I get the following error:

    c.executemany('INSERT INTO current VALUES(?,?,?)',values)
ValueError: parameters are of unsupported type

CL. · Accepted Answer · 2014-04-09 20:14:45Z

2

execute expects a sequence of parameters.

executemany works for multiple executions, so it expects a sequence of sequences of parameters:

values = ((lat_db,lon_db,sst_db),)
c.executemany('INSERT INTO current VALUES(?,?,?)',values)

This makes sense only if you want to insert multiple records:

values = ((lat_db1, lon_db1, sst_db1),
          (lat_db2, lon_db2, sst_db2))
c.executemany('INSERT INTO current VALUES(?,?,?)', values)

edited Apr 9, 2014 at 20:14

answered Apr 9, 2014 at 19:35

CL.

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4 Comments

jhc Over a year ago

should I adapt my create table statement to have float instead of real values?

CL. Over a year ago

This has nothing to do with the declared column type, which has no effect anyway. You are supposed to execute the code shown before trying to use float64 values together with the sqlite3 module.

jhc Over a year ago

I have done the changes, but the error persists. I have also changed the create table statement just to be sure, same thing.

CL. Over a year ago

Sorry, float64 already is compatible by default. The error was raised because lat_db is not a sequence.

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