From the documentation:
JSON files are preferred to CSV files, as JSON can represent RethinkDB
documents fully. If you’re importing from a CSV file, you should
include a header row with the field names, or use the --no-header
option with the --custom-header option to specify the names.
rethinkdb import -f users.csv --format csv --table test.users --no-header \
--custom-header id,username,email,password
Values in CSV imports will always be imported as strings. If you want
to convert those fields after import to the number data type, run an
update query that does the conversion. An example runnable in the Data
Explorer:
r.table('tablename').update(function(doc) {
return doc.merge({
field1: doc('field1').coerceTo('number'),
field2: doc('field2').coerceTo('number')
})
});