feature: 数据库连接与SQL集中管理，提高代码可读性

db/base.py

@@ -0,0 +1,80 @@
+# -*- coding: utf-8 -*-
+import logging
+from typing import List, Dict, Any, Optional, Tuple, Union
+
+from db.connection import DBConnectionManager
+
+
+class BaseDBOperator:
+    """基础数据库操作类"""
+    
+    def __init__(self, db_manager: DBConnectionManager):
+        self.db_manager = db_manager
+        self.LOG = logging.getLogger(self.__class__.__name__)
+    
+    def execute_query(self, sql: str, params: Optional[tuple] = None, fetch_one: bool = False) -> Union[List[Dict], Dict, None]:
+        """执行查询SQL"""
+        conn = self.db_manager.get_mysql_connection()
+        try:
+            with conn.cursor(dictionary=True) as cursor:
+                cursor.execute(sql, params or ())
+                if fetch_one:
+                    return cursor.fetchone()
+                return cursor.fetchall()
+        except Exception as e:
+            self.LOG.error(f"执行查询SQL出错: {e}, SQL: {sql}, 参数: {params}")
+            return None
+        finally:
+            conn.close()
+    
+    def execute_update(self, sql: str, params: Optional[tuple] = None) -> bool:
+        """执行更新SQL"""
+        conn = self.db_manager.get_mysql_connection()
+        try:
+            with conn.cursor() as cursor:
+                cursor.execute(sql, params or ())
+            conn.commit()
+            return True
+        except Exception as e:
+            self.LOG.error(f"执行更新SQL出错: {e}, SQL: {sql}, 参数: {params}")
+            conn.rollback()
+            return False
+        finally:
+            conn.close()
+    
+    def execute_batch(self, sql: str, params_list: List[tuple]) -> bool:
+        """批量执行SQL"""
+        if not params_list:
+            return True
+            
+        conn = self.db_manager.get_mysql_connection()
+        try:
+            with conn.cursor() as cursor:
+                cursor.executemany(sql, params_list)
+            conn.commit()
+            return True
+        except Exception as e:
+            self.LOG.error(f"批量执行SQL出错: {e}, SQL: {sql}, 参数数量: {len(params_list)}")
+            conn.rollback()
+            return False
+        finally:
+            conn.close()
+    
+    def execute_transaction(self, operations: List[Tuple[str, tuple]]) -> bool:
+        """执行事务"""
+        if not operations:
+            return True
+            
+        conn = self.db_manager.get_mysql_connection()
+        try:
+            with conn.cursor() as cursor:
+                for sql, params in operations:
+                    cursor.execute(sql, params)
+            conn.commit()
+            return True
+        except Exception as e:
+            self.LOG.error(f"执行事务出错: {e}, 操作数量: {len(operations)}")
+            conn.rollback()
+            return False
+        finally:
+            conn.close()