1132 If a column is nullable, make it optional by default in create_pydantic_model

docs/src/piccolo/serialization/index.rst

@@ -191,23 +191,45 @@ So if we want to disallow extra fields, we can do:
 Required fields
 ~~~~~~~~~~~~~~~
 
-You can specify which fields are required using the ``required``
-argument of :class:`Column <piccolo.columns.base.Column>`. For example:
+If a column has ``null=True``, then it creates an ``Optional`` field in the
+Pydantic model:
 
 .. code-block:: python
 
     class Band(Table):
-        name = Varchar(required=True)
+        name = Varchar(null=True)
+
+    BandModel = create_pydantic_model(Band)
+
+    # This is equivalent to:
+    from pydantic import BaseModel
+
+    class BandModel(BaseModel):
+        name: Optional[str] = None
+
+If the column has ``null=True``, but we still want the user to provide a value,
+then we can pass ``required=True`` to :class:`Column <piccolo.columns.base.Column>`:
+
+.. code-block:: python
+
+    class Band(Table):
+        name = Varchar(null=True, required=True)
 
     BandModel = create_pydantic_model(Band)
 
+    # This is equivalent to:
+    from pydantic import BaseModel
+
+    class BandModel(BaseModel):
+        name: str
+
     # Omitting the field raises an error:
     >>> BandModel()
     ValidationError - name field required
 
-You can override this behaviour using the ``all_optional`` argument. An example
-use case is when you have a model which is used for filtering, then you'll want
-all fields to be optional.
+If you don't want any of your fields to be required, you can use the
+``all_optional`` argument. An example use case is when you have a model which
+is used for filtering:
 
 .. code-block:: python
 
@@ -217,11 +239,10 @@ all fields to be optional.
     BandFilterModel = create_pydantic_model(
         Band,
         all_optional=True,
-        model_name='BandFilterModel',
     )
 
     # This no longer raises an exception:
-    >>> BandModel()
+    >>> BandFilterModel()
 
 Subclassing the model
 ~~~~~~~~~~~~~~~~~~~~~

piccolo/columns/base.py

@@ -153,7 +153,7 @@ class ColumnMeta:
     unique: bool = False
     index: bool = False
     index_method: IndexMethod = IndexMethod.btree
-    required: bool = False
+    required: t.Optional[bool] = None
     help_text: t.Optional[str] = None
     choices: t.Optional[t.Type[Enum]] = None
     secret: bool = False
@@ -459,7 +459,7 @@ def __init__(
         unique: bool = False,
         index: bool = False,
         index_method: IndexMethod = IndexMethod.btree,
-        required: bool = False,
+        required: t.Optional[bool] = None,
         help_text: t.Optional[str] = None,
         choices: t.Optional[t.Type[Enum]] = None,
         db_column_name: t.Optional[str] = None,

piccolo/utils/pydantic.py

@@ -243,10 +243,20 @@ def create_pydantic_model(
     for column in piccolo_columns:
         column_name = column._meta.name
 
-        is_optional = True if all_optional else not column._meta.required
+        #######################################################################
+        # Work out if the field should be optional
+
+        if all_optional:
+            is_optional = True
+        elif column._meta.required is not None:
+            # The user can force the field to be optional or not, irrespective
+            # of whether it's nullable in the database.
+            is_optional = not column._meta.required
+        else:
+            is_optional = column._meta.null
 
         #######################################################################
-        # Work out the column type
+        # Work out the field type
 
         if isinstance(column, (JSON, JSONB)):
             if deserialize_json:

tests/apps/fixtures/commands/test_shared.py

@@ -50,6 +50,7 @@ def test_shared(self):
                         "unique_col": "hello",
                         "null_col": None,
                         "not_null_col": "hello",
+                        "double_precision_col": 1.0,
                     }
                 ],
             }

tests/utils/test_pydantic.py

@@ -48,12 +48,17 @@ class Director(Table):
         pydantic_model = create_pydantic_model(table=Director)
 
         self.assertEqual(
-            pydantic_model.model_json_schema()["properties"]["email"]["anyOf"][
-                0
-            ]["format"],
+            pydantic_model.model_json_schema()["properties"]["email"][
+                "format"
+            ],
             "email",
         )
 
+        self.assertEqual(
+            pydantic_model.model_json_schema()["properties"]["email"]["type"],
+            "string",
+        )
+
         with self.assertRaises(ValidationError):
             pydantic_model(email="not a valid email")
 
@@ -121,8 +126,8 @@ class Band(Table):
 
         self.assertEqual(
             pydantic_model.model_json_schema()["properties"]["members"][
-                "anyOf"
-            ][0]["items"]["type"],
+                "items"
+            ]["type"],
             "string",
         )
 
@@ -132,7 +137,7 @@ def test_multidimensional_array(self):
         """
 
         class Band(Table):
-            members = Array(Array(Varchar(length=255)), required=True)
+            members = Array(Array(Varchar(length=255)))
 
         pydantic_model = create_pydantic_model(table=Band)
 
@@ -223,8 +228,8 @@ class Concert(Table):
 
         self.assertEqual(
             pydantic_model.model_json_schema()["properties"]["start_time"][
-                "anyOf"
-            ][0]["format"],
+                "format"
+            ],
             "time",
         )
 
@@ -281,13 +286,80 @@ class Ticket(Table):
             self.assertEqual(json, '{"code":"' + str(ticket_.code) + '"}')
 
         self.assertEqual(
-            pydantic_model.model_json_schema()["properties"]["code"]["anyOf"][
-                0
-            ]["format"],
+            pydantic_model.model_json_schema()["properties"]["code"]["format"],
             "uuid",
         )
 
 
+class TestRequired(TestCase):
+    """
+    Using the `required` attribute, we can force the field to be required or
+    not (overriding `column._meta.null`)
+    """
+
+    def test_required(self):
+        """
+        Make a null column required.
+        """
+
+        class Director(Table):
+            name = Varchar(null=True, required=True)
+
+        pydantic_model = create_pydantic_model(table=Director)
+
+        self.assertEqual(
+            pydantic_model.model_json_schema()["properties"]["name"]["type"],
+            "string",
+        )
+
+        with self.assertRaises(pydantic.ValidationError):
+            pydantic_model(name=None)
+
+    def test_not_required(self):
+        """
+        Make a column not required.
+        """
+
+        class Director(Table):
+            name = Varchar(null=False, required=False)
+
+        pydantic_model = create_pydantic_model(table=Director)
+
+        self.assertEqual(
+            pydantic_model.model_json_schema()["properties"]["name"]["anyOf"],
+            [
+                {"maxLength": 255, "type": "string"},
+                {"type": "null"},
+            ],
+        )
+
+        # Shouldn't raise an error:
+        pydantic_model(name=None)
+
+    def test_all_optional(self):
+        """
+        Makes all columns not required - useful for filters.
+        """
+
+        class Director(Table):
+            name = Varchar(null=False)
+
+        pydantic_model = create_pydantic_model(
+            table=Director, all_optional=True
+        )
+
+        self.assertEqual(
+            pydantic_model.model_json_schema()["properties"]["name"]["anyOf"],
+            [
+                {"maxLength": 255, "type": "string"},
+                {"type": "null"},
+            ],
+        )
+
+        # Shouldn't raise an error:
+        pydantic_model(name=None)
+
+
 class TestColumnHelpText(TestCase):
     """
     Make sure that columns with `help_text` attribute defined have the