fix: WorkflowNodeExecution.created_at may be earlier than WorkflowRun.created_at (#11070)

api/models/workflow.py

@@ -1,7 +1,7 @@
 import json
 from collections.abc import Mapping, Sequence
 from datetime import UTC, datetime
-from enum import Enum
+from enum import Enum, StrEnum
 from typing import Any, Optional, Union
 
 import sqlalchemy as sa
@@ -314,7 +314,7 @@ class Workflow(db.Model):
         )
 
 
-class WorkflowRunStatus(Enum):
+class WorkflowRunStatus(StrEnum):
     """
     Workflow Run Status Enum
     """
@@ -393,13 +393,13 @@ class WorkflowRun(db.Model):
     version = db.Column(db.String(255), nullable=False)
     graph = db.Column(db.Text)
     inputs = db.Column(db.Text)
-    status = db.Column(db.String(255), nullable=False)
-    outputs: Mapped[str] = db.Column(db.Text)
+    status = db.Column(db.String(255), nullable=False)  # running, succeeded, failed, stopped
+    outputs: Mapped[str] = mapped_column(sa.Text, default="{}")
     error = db.Column(db.Text)
     elapsed_time = db.Column(db.Float, nullable=False, server_default=db.text("0"))
     total_tokens = db.Column(db.Integer, nullable=False, server_default=db.text("0"))
     total_steps = db.Column(db.Integer, server_default=db.text("0"))
-    created_by_role = db.Column(db.String(255), nullable=False)
+    created_by_role = db.Column(db.String(255), nullable=False)  # account, end_user
     created_by = db.Column(StringUUID, nullable=False)
     created_at = db.Column(db.DateTime, nullable=False, server_default=db.text("CURRENT_TIMESTAMP(0)"))
     finished_at = db.Column(db.DateTime)