add support for bulk_update

docs/making_queries.md

@@ -146,10 +146,10 @@ await Note.objects.create(text="Send invoices.", completed=True)
 You need to pass a list of dictionaries of required fields to create multiple objects:
 
 ```python
-await Product.objects.bulk_create(
+await Note.objects.bulk_create(
     [
-        {"data": {"foo": 123}, "value": 123.456, "status": StatusEnum.RELEASED},
-        {"data": {"foo": 456}, "value": 456.789, "status": StatusEnum.DRAFT},
+        {"text": "Buy the groceries", "completed": False},
+        {"text": "Call Mum.", "completed": True},
 
     ]
 )
@@ -233,6 +233,18 @@ note = await Note.objects.first()
 await note.update(completed=True)
 ```
 
+### .bulk_update()
+
+You can also bulk update multiple objects at once by passing a list of objects and a list of fields to update.
+
+```python
+notes = await Note.objects.all()
+for note in notes :
+    note.completed = True
+
+await Note.objects.bulk_update(notes, fields=["completed"])
+```
+
 ## Convenience Methods
 
 ### .get_or_create()
@@ -252,7 +264,6 @@ if it doesn't exist, it will use `defaults` argument to create the new instance.
 !!! note
     Since `get_or_create()` is doing a [get()](#get), it can raise `MultipleMatches` exception.
 
-
 ### .update_or_create()
 
 To update an existing instance matching the query, or create a new one.

orm/models.py

@@ -1,3 +1,5 @@
+import enum
+import json
 import typing
 
 import databases
@@ -20,6 +22,8 @@
     "lte": "__le__",
 }
 
+MODEL = typing.TypeVar("MODEL", bound="Model")
+
 
 def _update_auto_now_fields(values, fields):
     for key, value in fields.items():
@@ -28,6 +32,15 @@ def _update_auto_now_fields(values, fields):
     return values
 
 
+def _convert_value(value):
+    if isinstance(value, dict):
+        return json.dumps(value)
+    elif isinstance(value, enum.Enum):
+        return value.name
+    else:
+        return value
+
+
 class ModelRegistry:
     def __init__(self, database: databases.Database) -> None:
         self.database = database
@@ -454,6 +467,43 @@ async def update(self, **kwargs) -> None:
 
         await self.database.execute(expr)
 
+    async def bulk_update(
+        self, objs: typing.List[MODEL], fields: typing.List[str]
+    ) -> None:
+        fields = {
+            key: field.validator
+            for key, field in self.model_cls.fields.items()
+            if key in fields
+        }
+        validator = typesystem.Schema(fields=fields)
+        new_objs = [
+            _update_auto_now_fields(validator.validate(value), self.model_cls.fields)
+            for value in [
+                {
+                    key: _convert_value(value)
+                    for key, value in obj.__dict__.items()
+                    if key in fields
+                }
+                for obj in objs
+            ]
+        ]
+        expr = (
+            self.table.update()
+            .where(
+                getattr(self.table.c, self.pkname) == sqlalchemy.bindparam(self.pkname)
+            )
+            .values(
+                {
+                    field: sqlalchemy.bindparam(field)
+                    for obj in new_objs
+                    for field in obj.keys()
+                }
+            )
+        )
+        pk_list = [{self.pkname: getattr(obj, self.pkname)} for obj in objs]
+        joined_list = [{**pk, **value} for pk, value in zip(pk_list, new_objs)]
+        await self.database.execute_many(str(expr), joined_list)
+
     async def get_or_create(
         self, defaults: typing.Dict[str, typing.Any], **kwargs
     ) -> typing.Tuple[typing.Any, bool]:

tests/test_columns.py

@@ -159,3 +159,43 @@ async def test_bulk_create():
     assert products[1].data == {"foo": 456}
     assert products[1].value == 456.789
     assert products[1].status == StatusEnum.DRAFT
+
+
+async def test_bulk_update():
+    await Product.objects.bulk_create(
+        [
+            {
+                "created_day": datetime.date.today(),
+                "data": {"foo": 123},
+                "value": 123.456,
+                "status": StatusEnum.RELEASED,
+            },
+            {
+                "created_day": datetime.date.today(),
+                "data": {"foo": 456},
+                "value": 456.789,
+                "status": StatusEnum.DRAFT,
+            },
+        ]
+    )
+    products = await Product.objects.all()
+    products[0].created_day = datetime.date.today() - datetime.timedelta(days=1)
+    products[1].created_day = datetime.date.today() - datetime.timedelta(days=1)
+    products[0].status = StatusEnum.DRAFT
+    products[1].status = StatusEnum.RELEASED
+    products[0].data = {"foo": 1234}
+    products[1].data = {"foo": 5678}
+    products[0].value = 345.5
+    products[1].value = 789.8
+    await Product.objects.bulk_update(
+        products, fields=["created_day", "status", "data", "value"]
+    )
+    products = await Product.objects.all()
+    assert products[0].created_day == datetime.date.today() - datetime.timedelta(days=1)
+    assert products[1].created_day == datetime.date.today() - datetime.timedelta(days=1)
+    assert products[0].status == StatusEnum.DRAFT
+    assert products[1].status == StatusEnum.RELEASED
+    assert products[0].data == {"foo": 1234}
+    assert products[1].data == {"foo": 5678}
+    assert products[0].value == 345.5
+    assert products[1].value == 789.8

tests/test_foreignkey.py

@@ -278,3 +278,22 @@ async def test_nullable_foreign_key():
 
     assert member.email == "dev@encode.io"
     assert member.team.pk is None
+
+
+async def test_bulk_update_with_relation():
+    album = await Album.objects.create(name="foo")
+    album2 = await Album.objects.create(name="bar")
+
+    await Track.objects.bulk_create(
+        [
+            {"name": "foo", "album": album, "position": 1, "title": "foo"},
+            {"name": "bar", "album": album, "position": 2, "title": "bar"},
+        ]
+    )
+    tracks = await Track.objects.all()
+    for track in tracks:
+        track.album = album2
+    await Track.objects.bulk_update(tracks, fields=["album"])
+    tracks = await Track.objects.all()
+    assert tracks[0].album.pk == album2.pk
+    assert tracks[1].album.pk == album2.pk