Refactor: replace count() > 0 check with exists() (#24583)

Co-authored-by: Yongtao Huang <99629139+hyongtao-db@users.noreply.github.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/models/model.py

@@ -17,7 +17,7 @@ if TYPE_CHECKING:
 import sqlalchemy as sa
 from flask import request
 from flask_login import UserMixin
-from sqlalchemy import Float, Index, PrimaryKeyConstraint, String, func, text
+from sqlalchemy import Float, Index, PrimaryKeyConstraint, String, exists, func, select, text
 from sqlalchemy.orm import Mapped, Session, mapped_column
 
 from configs import dify_config
@@ -1553,7 +1553,7 @@ class ApiToken(Base):
     def generate_api_key(prefix, n):
         while True:
             result = prefix + generate_string(n)
-            if db.session.query(ApiToken).where(ApiToken.token == result).count() > 0:
+            if db.session.scalar(select(exists().where(ApiToken.token == result))):
                 continue
             return result
 

api/models/workflow.py

@@ -7,7 +7,7 @@ from typing import TYPE_CHECKING, Any, Optional, Union
 from uuid import uuid4
 
 import sqlalchemy as sa
-from sqlalchemy import DateTime, orm
+from sqlalchemy import DateTime, exists, orm, select
 
 from core.file.constants import maybe_file_object
 from core.file.models import File
@@ -336,12 +336,13 @@ class Workflow(Base):
         """
         from models.tools import WorkflowToolProvider
 
-        return (
-            db.session.query(WorkflowToolProvider)
-            .where(WorkflowToolProvider.tenant_id == self.tenant_id, WorkflowToolProvider.app_id == self.app_id)
-            .count()
-            > 0
+        stmt = select(
+            exists().where(
+                WorkflowToolProvider.tenant_id == self.tenant_id,
+                WorkflowToolProvider.app_id == self.app_id,
+            )
         )
+        return db.session.execute(stmt).scalar_one()
 
     @property
     def environment_variables(self) -> Sequence[StringVariable | IntegerVariable | FloatVariable | SecretVariable]:
@@ -921,7 +922,7 @@ def _naive_utc_datetime():
 
 class WorkflowDraftVariable(Base):
     """`WorkflowDraftVariable` record variables and outputs generated during
-    debugging worfklow or chatflow.
+    debugging workflow or chatflow.
 
     IMPORTANT: This model maintains multiple invariant rules that must be preserved.
     Do not instantiate this class directly with the constructor.