feat(engine): 实现 DataRouter 数据库连接功能

src/factors/engine.py

@@ -24,6 +24,7 @@ from src.factors.dsl import (
 )
 from src.factors.compiler import DependencyExtractor
 from src.factors.translator import PolarsTranslator
+from src.data.storage import Storage
 
 
 @dataclass
@@ -78,13 +79,19 @@ class DataRouter:
 
         Args:
             data_source: 内存数据源，字典格式 {表名: DataFrame}
-                        为 None 时需要在子类中实现数据库连接
+                        为 None 时自动连接 DuckDB 数据库
         """
         self.data_source = data_source or {}
         self.is_memory_mode = data_source is not None
         self._cache: Dict[str, pl.DataFrame] = {}
         self._lock = threading.Lock()
 
+        # 数据库模式下初始化 Storage
+        if not self.is_memory_mode:
+            self._storage = Storage()
+        else:
+            self._storage = None
+
     def fetch_data(
         self,
         data_specs: List[DataSpec],
@@ -171,40 +178,105 @@ class DataRouter:
                 return self._cache[cache_key]
 
         if self.is_memory_mode:
-            if table_name not in self.data_source:
-                raise ValueError(f"内存数据源中缺少表: {table_name}")
-
-            df = self.data_source[table_name]
-
-            # 确保必需字段存在
-            for col in columns:
-                if col not in df.columns and col not in ["ts_code", "trade_date"]:
-                    raise ValueError(f"表 {table_name} 缺少字段: {col}")
-
-            # 过滤日期和股票
-            df = df.filter(
-                (pl.col("trade_date") >= start_date)
-                & (pl.col("trade_date") <= end_date)
+            df = self._load_from_memory(
+                table_name, columns, start_date, end_date, stock_codes
             )
-
-            if stock_codes is not None:
-                df = df.filter(pl.col("ts_code").is_in(stock_codes))
-
-            # 选择需要的列
-            select_cols = ["ts_code", "trade_date"] + [
-                c for c in columns if c in df.columns
-            ]
-            df = df.select(select_cols)
-
         else:
-            # TODO: 实现真实数据库连接（DuckDB）
-            raise NotImplementedError("数据库连接模式尚未实现")
+            df = self._load_from_database(
+                table_name, columns, start_date, end_date, stock_codes
+            )
 
         with self._lock:
             self._cache[cache_key] = df
 
         return df
 
+    def _load_from_memory(
+        self,
+        table_name: str,
+        columns: List[str],
+        start_date: str,
+        end_date: str,
+        stock_codes: Optional[List[str]] = None,
+    ) -> pl.DataFrame:
+        """从内存数据源加载数据。"""
+        if table_name not in self.data_source:
+            raise ValueError(f"内存数据源中缺少表: {table_name}")
+
+        df = self.data_source[table_name]
+
+        # 确保必需字段存在
+        for col in columns:
+            if col not in df.columns and col not in ["ts_code", "trade_date"]:
+                raise ValueError(f"表 {table_name} 缺少字段: {col}")
+
+        # 过滤日期和股票
+        df = df.filter(
+            (pl.col("trade_date") >= start_date) & (pl.col("trade_date") <= end_date)
+        )
+
+        if stock_codes is not None:
+            df = df.filter(pl.col("ts_code").is_in(stock_codes))
+
+        # 选择需要的列
+        select_cols = ["ts_code", "trade_date"] + [
+            c for c in columns if c in df.columns
+        ]
+        return df.select(select_cols)
+
+    def _load_from_database(
+        self,
+        table_name: str,
+        columns: List[str],
+        start_date: str,
+        end_date: str,
+        stock_codes: Optional[List[str]] = None,
+    ) -> pl.DataFrame:
+        """从 DuckDB 数据库加载数据。
+
+        利用 Storage.load_polars() 方法，支持 SQL 查询下推。
+        """
+        if self._storage is None:
+            raise RuntimeError("Storage 未初始化")
+
+        # 检查表是否存在
+        if not self._storage.exists(table_name):
+            raise ValueError(f"数据库中不存在表: {table_name}")
+
+        # 构建查询参数
+        # Storage.load_polars 目前只支持单个 ts_code，需要处理列表情况
+        if stock_codes is not None and len(stock_codes) == 1:
+            ts_code_filter = stock_codes[0]
+        else:
+            ts_code_filter = None
+
+        try:
+            # 从数据库加载原始数据
+            df = self._storage.load_polars(
+                name=table_name,
+                start_date=start_date,
+                end_date=end_date,
+                ts_code=ts_code_filter,
+            )
+        except Exception as e:
+            raise RuntimeError(f"从数据库加载表 {table_name} 失败: {e}")
+
+        # 如果 stock_codes 是列表且长度 > 1，在内存中过滤
+        if stock_codes is not None and len(stock_codes) > 1:
+            df = df.filter(pl.col("ts_code").is_in(stock_codes))
+
+        # 检查必需字段
+        for col in columns:
+            if col not in df.columns and col not in ["ts_code", "trade_date"]:
+                raise ValueError(f"表 {table_name} 缺少字段: {col}")
+
+        # 选择需要的列
+        select_cols = ["ts_code", "trade_date"] + [
+            c for c in columns if c in df.columns
+        ]
+
+        return df.select(select_cols)
+
     def _assemble_wide_table(
         self,
         table_data: Dict[str, pl.DataFrame],
@@ -275,6 +347,11 @@ class DataRouter:
         with self._lock:
             self._cache.clear()
 
+        # 数据库模式下清理 Storage 连接（可选）
+        if not self.is_memory_mode and self._storage is not None:
+            # Storage 使用单例模式，不需要关闭连接
+            pass
+
 
 class ExecutionPlanner:
     """执行计划生成器。