整理配置和代码入口，增加部分测试。

sync_state_machine/datasource/db/handler.py

@@ -0,0 +1,68 @@
+"""BaseDbHandler - DB Handler 基类。"""
+
+from __future__ import annotations
+
+from typing import Any, Dict, List, Optional, Set, TypeVar, TYPE_CHECKING
+
+from pydantic import BaseModel
+
+from ...common.type_safety import get_pydantic_model_fields
+from ..handler import BaseNodeHandler
+
+if TYPE_CHECKING:
+    from ...common.sync_node import SyncNode
+    from .datasource import DbDataSource
+
+T = TypeVar("T", bound=BaseModel)
+
+
+class BaseDbHandler(BaseNodeHandler[T]):
+    """数据库 Handler 基类。"""
+
+    def __init__(
+        self,
+        datasource: "DbDataSource",
+        node_type: str,
+        node_class: type["SyncNode[T]"],
+        schema: type[T],
+    ):
+        super().__init__(node_type, node_class, schema)
+        self.datasource = datasource
+        self.update_schemas: List[type] = []
+        self._target_project_ids: Optional[Set[str]] = None
+
+    def set_target_project_ids(self, target_project_ids: List[str]) -> None:
+        if target_project_ids:
+            self._target_project_ids = {str(item) for item in target_project_ids if str(item)}
+        else:
+            self._target_project_ids = None
+
+    def get_update_fields(self, *, exclude: frozenset = frozenset({"id"})) -> List[str]:
+        fields: set[str] = set()
+        for schema in self.update_schemas:
+            for field_name in get_pydantic_model_fields(schema):
+                if field_name not in exclude:
+                    fields.add(field_name)
+        return sorted(fields)
+
+    def _create_basic_node(self, data: Dict[str, Any], depend_ids: Optional[List[str]] = None) -> "SyncNode[T]":
+        data_id = self.extract_id(data)
+        if self._collection is None:
+            raise RuntimeError("Collection not set. Call set_collection() before creating nodes.")
+
+        if data_id:
+            existing_node = self._collection.get_by_data_id(self.node_type, data_id)
+            if existing_node is not None:
+                existing_node.depend_ids = list(depend_ids or [])
+                existing_node.set_data(data.copy())
+                existing_node.set_origin_data(data.copy())
+                return existing_node
+
+        node_id = self._collection.generate_node_id()
+        return self.node_class(
+            node_id=node_id,
+            data_id=data_id,
+            data=data.copy(),
+            depend_ids=depend_ids or [],
+            origin_data=data.copy(),
+        )