let say i have a table with the record that compare the product price with
the previous product price
e.g.
*models/db.py*
def on_define_nav(table):
table.daily_return.compute = lambda r: float(r['nav_per_unit'] ) -
float(r['previous_nav_per_unit'] )
table.daily_return_percentage.compute = lambda r: ((float(r['nav_per_unit']
) - float(r['previous_nav_per_unit'] ) ) / float(r['previous_nav_per_unit']
) ) * 100
db.define_table('nav',
Field('product', 'reference product'),
Field('nav_date', 'date'),
Field('nav_per_unit', 'double'),
Field('previous_nav_per_unit', 'double'),
Field('daily_return', 'double'),
Field('daily_return_percentage', 'double'),
on_define = on_define_nav,
format = lambda r: '%s (%s) : %s' % (r.product.name, r.nav_date,
r.nav_per_unit) )
*currently import csv*
product nav_date nav_per_unit previous_nav_per_unit daily_return
daily_return_percentage
1 2017-02-01 1283.6907 1283.46 0.2307 0.0179748492
2 2017-02-01 1493.583 1493.58 0.003 0.0002008597
1 2017-02-02 1289.44 1288.75 0.69 0.0535402522
*expected import csv (scrape data from another web)*
product nav_date nav_per_unit
1 2017-02-01 1283.6907
2 2017-02-01 1493.583
1 2017-02-02 1289.44
currently when i insert the data with either from web or csv i must define
previous value during the insert, is it possible to get previous inserted
record with the same product id in web2py dal?
thanks and best regards,
stifan
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