This commit add an extra parameter 'fill_temporal' to read_group which allows
the orm to add missing groups for date intervals. This is useful for charts.
Suppose that we are in a use case where data are grouped by a date fields
(typically months but it could be another interval) and displayed in a Bar Chart
or a Line Char.
Let's says a request has to group records by month for August, September
and ...December. If we don't changed anything, we would get a Bar Chart
looking like this :
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Aug Sep D
December follows directly after September, it can be unintuitive for the
user, so we change that. We add some fake records for each missing months
between the earliest and the lastest date of the result
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Aug Sep Oct Nov Dec
This commit is part of task #1835644
The caller of `read_group` can now provide the aggregating function to use for
a given field:
# set aggregating operator for fields 'foo' and 'bar'
model.read_group(domain, ['foo:sum', 'bar:avg'], ...)
One can also aggregate the same field several times, by giving a specific
output name for each:
# aggregate 'foo' with both 'min' and 'max'
model.read_group(domain, ['foomin:min(foo)', 'foomax:max(foo)'], ...)
The attribute `group_expand` allows to reorder and add empty groups to the
result of `read_group`. Enable this feature for other fields than many2one
fields.
Francois Volral