Use SQLAlchemy defaults in fields

examples/sqla/models.py

@@ -2,6 +2,7 @@
 from datetime import datetime
 
 from sqlalchemy import (
+    Boolean,
     Column,
     Date,
     DateTime,
@@ -51,9 +52,10 @@ class Post(Base):
     id = Column(Integer, primary_key=True)
     title = Column(String(100), nullable=False)
     text = Column(Text, nullable=False)
-    date = Column(Date)
-    status = Column(Enum(Status))
+    date = Column(Date, default=datetime.today)
+    status = Column(Enum(Status), default=Status.PENDING)
     created_at = Column(DateTime, default=datetime.utcnow)
+    is_public = Column(Boolean, default=True, nullable=False)
 
     publisher_id = Column(Integer, ForeignKey(User.id))
     publisher = relationship(User, back_populates="posts")

starlette_admin/base.py

@@ -406,13 +406,20 @@ async def _render_create(self, request: Request) -> Response:
         request.state.action = RequestAction.CREATE
         identity = request.path_params.get("identity")
         model = self._find_model_from_identity(identity)
-        config = {"request": request, "title": model.title(request), "model": model}
+        dict_obj = self.defaults_to_dict(request, model, RequestAction.CREATE)
+        config = {
+            "request": request,
+            "title": model.title(request),
+            "model": model,
+            "obj": dict_obj,
+        }
         if not model.is_accessible(request) or not model.can_create(request):
             raise HTTPException(HTTP_403_FORBIDDEN)
         if request.method == "GET":
             return self.templates.TemplateResponse(model.create_template, config)
         form = await request.form()
-        dict_obj = await self.form_to_dict(request, form, model, RequestAction.CREATE)
+        form_dict = await self.form_to_dict(request, form, model, RequestAction.CREATE)
+        dict_obj.update(form_dict)
         try:
             obj = await model.create(request, dict_obj)
         except FormValidationError as exc:
@@ -494,6 +501,17 @@ async def _render_error(
             status_code=exc.status_code,
         )
 
+    def defaults_to_dict(
+        self,
+        request: Request,
+        model: BaseModelView,
+        action: RequestAction,
+    ) -> dict[str, Any]:
+        data = {}
+        for field in model.get_fields_list(request, action):
+            data[field.name] = field.default
+        return data
+
     async def form_to_dict(
         self,
         request: Request,

starlette_admin/contrib/sqla/converters.py

@@ -11,6 +11,7 @@
     RelationshipProperty,
 )
 from sqlalchemy.sql.elements import ColumnElement, Label
+from sqlalchemy.sql.schema import ScalarElementColumnDefault
 from starlette_admin.contrib.sqla.exceptions import NotSupportedColumn
 from starlette_admin.contrib.sqla.fields import FileField, ImageField
 from starlette_admin.converters import BaseModelConverter, converts
@@ -130,15 +131,28 @@ def _field_common(
                 "exclude_from_edit": True,
                 "exclude_from_create": True,
             }
+
+        default_value = ""
+        help_text = column.comment
+        if column.default:
+            if isinstance(column.default, ScalarElementColumnDefault):
+                default_value = column.default.arg
+            elif help_text:
+                # We can't evaluate even CallableColumnDefault because it requires execution context
+                help_text = f"{help_text}. Defaulted to {column.default.arg}"
+            else:
+                help_text = f"Defaulted to {column.default.arg}"
+
         return {
             "name": name,
-            "help_text": column.comment,
+            "help_text": help_text,
             "required": (
                 not column.nullable
                 and not isinstance(column.type, (Boolean,))
                 and not column.default
                 and not column.server_default
             ),
+            "default": default_value,
         }
 
     @classmethod

starlette_admin/fields.py

@@ -54,6 +54,7 @@ class BaseField:
         search_builder_type: datatable columns.searchBuilderType, For more information
             [click here](https://datatables.net/reference/option/columns.searchBuilderType)
         required: Indicate if the fields is required
+        default: Default value for the field
         exclude_from_list: Control field visibility in list page
         exclude_from_detail: Control field visibility in detail page
         exclude_from_create: Control field visibility in create page
@@ -74,6 +75,7 @@ class BaseField:
     id: str = ""
     search_builder_type: Optional[str] = "default"
     required: Optional[bool] = False
+    default: str = ""
     exclude_from_list: Optional[bool] = False
     exclude_from_detail: Optional[bool] = False
     exclude_from_create: Optional[bool] = False
@@ -84,7 +86,7 @@ class BaseField:
     form_template: str = "forms/input.html"
     label_template: str = "forms/_label.html"
     display_template: str = "displays/text.html"
-    error_class = "is-invalid"
+    error_class: str = "is-invalid"
 
     def __post_init__(self) -> None:
         if self.label is None: