From ad5bbfe24c8d00d3bc4b2ae96cb583c141ae27dd Mon Sep 17 00:00:00 2001
From: Alban Gruin
Date: Fri, 27 Jan 2017 22:48:47 +0100
Subject: Création de différentes classes permettant d'effectuer un group by
 simple  * GroupedCompiler rajoute une étape à get_group_by() pour insérer de
 manière simple les champs à    grouper  * GroupedQuery rajoute une liste
 stockant les champs à grouper  * GroupedQuerySet implémente la fonction
 group_by()  * GroupedManager change le type de QuerySet par défaut pour
 GroupedQuerySet

Le manager des cours se base sur GroupedManager
---
 db.py | 34 ++++++++++++++++++++++++++++------
 1 file changed, 28 insertions(+), 6 deletions(-)

(limited to 'db.py')

diff --git a/db.py b/db.py
index df9ceda..e75adca 100644
--- a/db.py
+++ b/db.py
@@ -1,18 +1,40 @@
+from django.db import connections
 from django.db.models import Manager
 from django.db.models.query import QuerySet
+from django.db.models.sql.compiler import SQLCompiler
 from django.db.models.sql.query import Query
+from django.db.models.sql.where import WhereNode
+
+
+class GroupedCompiler(SQLCompiler):
+    def get_group_by(self, select, order_by):
+        result = super(GroupedCompiler, self).get_group_by(select, order_by)
+        expressions = []
+        for expr in self.query.real_group_by:
+            ref = expr if hasattr(expr, "as_sql") else self.query.resolve_ref(expr)
+            sql, params = self.compile(ref)
+            result.append((sql, params))
+
+        return result
 
 
 class GroupedQuery(Query):
-    def add_grouping(self, *grouping):
-        if self.group_by is None:
-            self.group_by = []
+    def __init__(self, model, where=WhereNode):
+        super(GroupedQuery, self).__init__(model, where)
+        self.real_group_by = []
 
-        if isinstance(self.group_by, list):
-            self.group_by.extend(grouping)
+    def add_grouping(self, *grouping):
+        self.real_group_by.extend(grouping)
 
     def clear_grouping(self):
-        self.group_by = None
+        self.real_group_by = []
+
+    def get_compiler(self, using=None, connection=None):
+        if using is None and connection is None:
+            raise ValueError("Need either using or connection")
+        if using:
+            connection = connections[using]
+        return GroupedCompiler(self, connection, using)
 
 
 class GroupedQuerySet(QuerySet):
-- 
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