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Code Issues 32 Releases Wiki Activity

Fixed #3566 -- Added support for aggregation to the ORM. See the documentation for details on usage.

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Many thanks to:
 * Nicolas Lara, who worked on this feature during the 2008 Google Summer of Code.
 * Alex Gaynor for his help debugging and fixing a number of issues.
 * Justin Bronn for his help integrating with contrib.gis.
 * Karen Tracey for her help with cross-platform testing.
 * Ian Kelly for his help testing and fixing Oracle support.
 * Malcolm Tredinnick for his invaluable review notes.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9742 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Russell Keith-Magee
2009-01-15 11:06:34 +00:00
parent 50a293a0c3
commit cc4e4d9aee
30 changed files with 2357 additions and 325 deletions
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53
django/db/models/sql/datastructures.py
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@@ -25,59 +25,6 @@ class RawValue(object):
def __init__(self, value):
self.value = value
class Aggregate(object):
"""
Base class for all aggregate-related classes (min, max, avg, count, sum).
"""
def relabel_aliases(self, change_map):
"""
Relabel the column alias, if necessary. Must be implemented by
subclasses.
"""
raise NotImplementedError
def as_sql(self, quote_func=None):
"""
Returns the SQL string fragment for this object.
The quote_func function is used to quote the column components. If
None, it defaults to doing nothing.
Must be implemented by subclasses.
"""
raise NotImplementedError
class Count(Aggregate):
"""
Perform a count on the given column.
"""
def __init__(self, col='*', distinct=False):
"""
Set the column to count on (defaults to '*') and set whether the count
should be distinct or not.
"""
self.col = col
self.distinct = distinct
def relabel_aliases(self, change_map):
c = self.col
if isinstance(c, (list, tuple)):
self.col = (change_map.get(c[0], c[0]), c[1])
def as_sql(self, quote_func=None):
if not quote_func:
quote_func = lambda x: x
if isinstance(self.col, (list, tuple)):
col = ('%s.%s' % tuple([quote_func(c) for c in self.col]))
elif hasattr(self.col, 'as_sql'):
col = self.col.as_sql(quote_func)
else:
col = self.col
if self.distinct:
return 'COUNT(DISTINCT %s)' % col
else:
return 'COUNT(%s)' % col
class Date(object):
"""
Add a date selection column.