dump csv from sqlalchemy

Question

For some reason, I want to dump a table from a database (sqlite3) in the form of a csv file. I'm using a python script with elixir (based on sqlalchemy) to modify the database. I was wondering if there is any way to dump the table I use to csv.

I've seen sqlalchemy serializer but it doesn't seem to be what I want. Am I doing it wrong? Should I call the sqlite3 python module after closing my sqlalchemy session to dump to a file instead? Or should I use something homemade?

Answer 1

There are numerous ways to achieve this, including a simple os.system() call to the sqlite3 utility if you have that installed, but here's roughly what I'd do from Python:

import sqlite3
import csv

con = sqlite3.connect('mydatabase.db')
outfile = open('mydump.csv', 'wb')
outcsv = csv.writer(outfile)

cursor = con.execute('select * from mytable')

# dump column titles (optional)
outcsv.writerow(x[0] for x in cursor.description)
# dump rows
outcsv.writerows(cursor.fetchall())

outfile.close()

Answer 2

Modifying Peter Hansen's answer here a bit, to use SQLAlchemy instead of raw db access

import csv
outfile = open('mydump.csv', 'wb')
outcsv = csv.writer(outfile)
records = session.Query(MyModel).all()
[ outcsv.writerow(curr.field_one, curr.field_two)  for curr in records ]
# or maybe use outcsv.writerows(records)

outfile.close()