How to show @property field in ModelView

[ps96068]

Hello

in one my SQLAlchemy model i have a @Property field, look at the code:

class UserActivity(Base):
    __tablename__ = "user_activity"

    id: Mapped[int] = mapped_column(primary_key=True, unique=True, nullable=False)
    user_id: Mapped[int] = mapped_column(ForeignKey("users.id"), nullable=False, index=True)
    session_start: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), nullable=False)  
    session_end: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True, index=True) 
    

    @property
    def session_duration(self) -> int | None:
        if self.session_end:
            delta = self.session_end - self.session_start
            return int(delta.total_seconds())
        return None

if i create ModelView:

class UserActivityView(ModelView):
    fields = [
        "id",
        "user_id",
        "session_start",
        "session_end",
        "session_duration",
    ]

have an errore:

ValueError: Can't find column with key session_duration

can somebody help me to solve this problem?

thanks in advance

[jowilf]

You are having this error because session_duration is not an SQLAlchemy column and cannot be auto-detected by the current converter logic. In that case, you have to set the field:

class UserActivityView(ModelView):
    fields = [
        "id",
        "session_start",
        "session_end",
        "user_id",
        IntegerField("session_duration", exclude_from_edit=True, exclude_from_create=True),
    ]