Add NULLS ordering

issue5858
review27651002

CHANGELOG

@@ -1,3 +1,4 @@
+* Add NULLS ordering
 * Add context domain on ir.action.act_window
 * Allow None limit in action window
 * Add has_window_functions on Database

doc/ref/models/models.rst

@@ -378,7 +378,9 @@ Class attributes are:
 
     where the first element of the tuple is a field name of the model and the
     second is the sort ordering as `ASC` for ascending or `DESC` for
-    descending.
+    descending. This second element may contain 'NULLS FIRST' or 'NULLS LAST'
+    to sort null values before or after non-null values. If neither is
+    specified the default behavior of the backend is used.
 
     In case the field used for the first element is a :class:`fields.Many2One`,
     it is also possible to use the dotted notation to sort on a specific field
@@ -687,14 +689,13 @@ Class methods:
 sequence_ordered
 ================
 
-.. method:: sequence_ordered([field_name, [field_label, [order, [null_first]]]])
+.. method:: sequence_ordered([field_name, [field_label, [order]]])
 
 Retuns a mixin_ class which defines the order of a :class:`ModelSQL` with an
 :class:`trytond.model.fields.Integer` field. field_name indicates the name of
 the field to be created and its default values is `sequence`. field_label
 defines the label which will be used by the field and defaults to `Sequence`.
-Order specifies the order direction and defaults to `ASC` and null first
-if the null values should be ordered first and defaults to `True`.
+Order specifies the order direction and defaults to `ASC NULLS FIRST`.
 
 
 .. _mixin: http://en.wikipedia.org/wiki/Mixin

trytond/backend/mysql/database.py

@@ -75,7 +75,9 @@ class Database(DatabaseInterface):
 
     _list_cache = None
     _list_cache_timestamp = None
-    flavor = Flavor(max_limit=18446744073709551610, function_mapping=MAPPING)
+    flavor = Flavor(
+        max_limit=18446744073709551610, function_mapping=MAPPING,
+        null_ordering=False)
 
     def connect(self):
         return self

trytond/backend/sqlite/database.py

@@ -221,7 +221,8 @@ class Database(DatabaseInterface):
 
     _local = threading.local()
     _conn = None
-    flavor = Flavor(paramstyle='qmark', function_mapping=MAPPING)
+    flavor = Flavor(
+        paramstyle='qmark', function_mapping=MAPPING, null_ordering=False)
     IN_MAX = 200
 
     def __new__(cls, name=':memory:'):

trytond/model/modelsql.py

@@ -4,7 +4,8 @@ import datetime
 from itertools import islice, izip, chain, ifilter
 from collections import OrderedDict
 
-from sql import Table, Column, Literal, Desc, Asc, Expression, Null
+from sql import (Table, Column, Literal, Desc, Asc, Expression, Null,
+    NullsFirst, NullsLast)
 from sql.functions import CurrentTimestamp, Extract
 from sql.conditionals import Coalesce
 from sql.operators import Or, And, Operator
@@ -1149,14 +1150,25 @@ class ModelSQL(ModelStorage):
             'DESC': Desc,
             'ASC': Asc,
             }
+        null_ordering_types = {
+            'NULLS FIRST': NullsFirst,
+            'NULLS LAST': NullsLast,
+            None: lambda _: _
+            }
         if order is None or order is False:
             order = cls._order
         for oexpr, otype in order:
             fname, _, extra_expr = oexpr.partition('.')
             field = cls._fields[fname]
-            Order = order_types[otype.upper()]
+            otype = otype.upper()
+            try:
+                otype, null_ordering = otype.split(' ', 1)
+            except ValueError:
+                null_ordering = None
+            Order = order_types[otype]
+            NullOrdering = null_ordering_types[null_ordering]
             forder = field.convert_order(oexpr, tables, cls)
-            order_by.extend((Order(o) for o in forder))
+            order_by.extend((NullOrdering(Order(o)) for o in forder))
 
         # construct a clause for the rules :
         domain = Rule.domain_get(cls.__name__, mode='read')

trytond/model/order.py

@@ -1,14 +1,10 @@
 # This file is part of Tryton.  The COPYRIGHT file at the toplevel of this
 # repository contains the full copyright notices and license terms.
-from sql import Null, Column
-from sql.operators import Equal, NotEqual
-from sql.conditionals import Case
-
 from trytond.model import fields
 
 
 def sequence_ordered(field_name='sequence', field_label='Sequence',
-        order='ASC', null_first=True):
+        order='ASC NULLS FIRST'):
     "Returns a mixin to order the model by order fields"
 
     class SequenceOrderedMixin(object):
@@ -20,14 +16,4 @@ def sequence_ordered(field_name='sequence', field_label='Sequence',
             cls._order = [(field_name, order)] + cls._order
 
     setattr(SequenceOrderedMixin, field_name, fields.Integer(field_label))
-
-    @classmethod
-    def order_function(cls, tables):
-        table, _ = tables[None]
-        operator = Equal
-        if not null_first:
-            operator = NotEqual
-        field = Column(table, field_name)
-        return [Case((operator(field, Null), 0), else_=1), field]
-    setattr(SequenceOrderedMixin, 'order_%s' % field_name, order_function)
     return SequenceOrderedMixin

trytond/tests/__init__.py

@@ -178,6 +178,7 @@ def register():
         TestHistoryLine,
         FieldContextChild,
         FieldContextParent,
+        NullOrder,
         module='tests', type_='model')
     Pool.register(
         TestWizard,

trytond/tests/model.py

@@ -13,6 +13,7 @@ __all__ = [
     'Union', 'UnionUnion',
     'Model4UnionTree1', 'Model4UnionTree2', 'UnionTree',
     'SequenceOrderedModel',
+    'NullOrder',
     ]
 
 
@@ -161,3 +162,9 @@ class UnionTree(UnionMixin, ModelSQL):
 class SequenceOrderedModel(sequence_ordered(), ModelSQL):
     'Sequence Ordered Model'
     __name__ = 'test.order.sequence'
+
+
+class NullOrder(ModelSQL):
+    "Null Order"
+    __name__ = 'test.null_order'
+    integer = fields.Integer('Integer')

trytond/tests/test_modelsql.py

@@ -133,6 +133,32 @@ class ModelSQLTestCase(unittest.TestCase):
             TargetModel.name.string, TargetModel.__doc__)
         self.assertEqual(err.message, msg)
 
+    @with_transaction()
+    def test_null_ordering(self):
+        'Test NULL ordering'
+        pool = Pool()
+        NullOrder = pool.get('test.null_order')
+
+        NullOrder.create([{
+                    'integer': 1,
+                    }, {
+                    'integer': 3,
+                    }, {
+                    'integer': None,
+                    }])
+        integers = NullOrder.search([], order=[('integer', 'ASC NULLS FIRST')])
+        self.assertListEqual([i.integer for i in integers], [None, 1, 3])
+
+        integers = NullOrder.search(
+            [], order=[('integer', 'DESC NULLS FIRST')])
+        self.assertListEqual([i.integer for i in integers], [None, 3, 1])
+
+        integers = NullOrder.search([], order=[('integer', 'ASC NULLS LAST')])
+        self.assertListEqual([i.integer for i in integers], [1, 3, None])
+
+        integers = NullOrder.search([], order=[('integer', 'DESC NULLS LAST')])
+        self.assertListEqual([i.integer for i in integers], [3, 1, None])
+
 
 def suite():
     return unittest.TestLoader().loadTestsFromTestCase(ModelSQLTestCase)