aaa46ef282
This commit implements a complete migration from JSON-based configuration to .env environment variables, providing better security and flexibility. Key Changes: - Add python-dotenv dependency for environment variable support - Create config/env_loader.py with type conversion utilities - Add from_env() class methods to all config dataclasses - Update ConfigLoader to prioritize environment variables - Add save_to_env() method for .env file management - Implement database connection factory pattern - Add base DAO and connection classes for better abstraction - Support both SQL Server and MySQL with unified interface - Create migration script (scripts/migrate_to_env.py) - Update GUI to read/write .env files - Add comprehensive migration documentation New Files: - config/env_loader.py - Environment variable loader - db/base_connection.py - Base database connection interface - db/base_dao.py - Base DAO with common utilities - db/connection_factory.py - Factory for creating connections - db/mysql_connection.py - MySQL-specific connection - db/sqlserver_connection.py - SQL Server-specific connection - db/table_name_converter.py - SQL dialect converter - scripts/migrate_to_env.py - Configuration migration tool - docs/ENV_MIGRATION.md - Complete migration guide - .env.example - Environment variable template Testing: - Verified MySQL connection (8.0.44) - Tested all DAO operations - Confirmed 150 tables accessible - Validated configuration loading Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
101 lines
2.7 KiB
Python
101 lines
2.7 KiB
Python
"""
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DAO 基类
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提供数据访问对象的通用方法和辅助函数
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"""
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from typing import Optional
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from config.schema import DatabaseType
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from db.base_connection import BaseDatabaseConnection
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from db.connection import get_connection
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from db.table_name_converter import TableNameConverter
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class BaseDAO:
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"""数据访问对象基类"""
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def __init__(self):
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"""初始化 DAO"""
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self.db: Optional[BaseDatabaseConnection] = None
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# 从配置文件加载数据库类型
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from config.loader import ConfigLoader
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app_config = ConfigLoader.load()
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self._db_type = app_config.database.db_type
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def __enter__(self):
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"""进入上下文管理器，建立数据库连接"""
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self.db = get_connection()
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self.db.connect()
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return self
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def __exit__(self, exc_type, exc_val, exc_tb):
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"""退出上下文管理器，关闭数据库连接"""
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if self.db:
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self.db.disconnect()
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def close(self):
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"""关闭数据库连接"""
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if self.db:
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self.db.disconnect()
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def _convert_sql(self, sql: str) -> str:
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"""
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根据当前数据库类型转换 SQL 语句中的表名
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Args:
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sql: 原始 SQL 语句（SQL Server 格式）
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Returns:
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转换后的 SQL 语句
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"""
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if self._db_type == DatabaseType.MYSQL:
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# SQL Server → MySQL
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return TableNameConverter.convert_sql(sql, 'mysql')
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return sql
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def _get_placeholder(self) -> str:
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"""
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获取当前数据库类型的参数占位符
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Returns:
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SQL Server 返回 "?"，MySQL 返回 "%s"
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"""
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if self._db_type == DatabaseType.MYSQL:
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return "%s"
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return "?"
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def _build_placeholders(self, count: int) -> str:
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"""
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构建参数占位符字符串
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Args:
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count: 占位符数量
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Returns:
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占位符字符串，如 "?, ?, ?" 或 "%s, %s, %s"
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"""
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placeholder = self._get_placeholder()
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return ", ".join([placeholder for _ in range(count)])
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def _build_in_clause_placeholders(self, count: int) -> str:
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"""
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构建 IN 子句的参数占位符字符串
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Args:
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count: 占位符数量
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Returns:
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IN 子句占位符字符串，如 "?, ?, ?" 或 "%s, %s, %s"
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"""
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placeholder = self._get_placeholder()
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return ", ".join([placeholder for _ in range(count)])
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def _get_connection(self):
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"""
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获取数据库连接
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Returns:
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数据库连接对象
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"""
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return get_connection()
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