feat: define model class for entity repository

src/backend/base/langflow/services/database/models/repo.py

@@ -0,0 +1,31 @@
+from abc import ABC, abstractmethod
+from typing import Generic, TypeVar, List, Optional
+from sqlmodel import SQLModel, Session
+
+
+T = TypeVar("T", bound=SQLModel)
+
+
+class AbstractRepository(ABC, Generic[T]):
+    def __init__(self, session: Session):
+        self.session = session
+
+    @abstractmethod
+    def add(self, entity: T) -> T:
+        pass
+
+    @abstractmethod
+    def get(self, id: int) -> Optional[T]:
+        pass
+
+    @abstractmethod
+    def list(self) -> List[T]:
+        pass
+
+    @abstractmethod
+    def update(self, entity: T) -> T:
+        pass
+
+    @abstractmethod
+    def delete(self, id: int) -> None:
+        pass