feat: 实现教师资料更新、操作日志和系统设置功能

新增教师资料更新功能，包括个人信息修改和密码更新
添加操作日志记录系统，记录用户关键操作
实现系统设置模块，支持动态配置系统参数
重构数据库模型，新增教师表和系统设置表
优化成绩录入逻辑，支持平时分、期中和期末成绩计算
添加数据导出功能，支持学生、教师和成绩数据导出
完善管理员后台，增加统计图表和操作日志查看

backend/config/database.js

@@ -1,36 +1,64 @@
-const mysql = require('mysql2/promise');
-require('dotenv').config();
+const sqlite3 = require('sqlite3').verbose();
+const path = require('path');
+const fs = require('fs');
 
-const pool = mysql.createPool({
-  host: process.env.DB_HOST || 'localhost',
-  user: process.env.DB_USER || 'root',
-  password: process.env.DB_PASSWORD || '123456',
-  database: process.env.DB_NAME || 'score_management',
-  waitForConnections: true,
-  connectionLimit: 10,
-  queueLimit: 0
-});
+const dbPath = path.resolve(__dirname, '../database.sqlite');
+const db = new sqlite3.Database(dbPath);
 
-// 封装基本查询方法
-const query = async (sql, params) => {
-    try {
-        const [rows] = await pool.execute(sql, params);
-        return rows;
-    } catch (error) {
-        console.error('Database query error:', error);
-        throw error;
-    }
+// Promisify query method
+const query = (sql, params = []) => {
+    return new Promise((resolve, reject) => {
+        // Handle SELECT vs INSERT/UPDATE/DELETE
+        const trimmedSql = sql.trim().toUpperCase();
+        if (trimmedSql.startsWith('SELECT') || trimmedSql.startsWith('PRAGMA')) {
+            db.all(sql, params, (err, rows) => {
+                if (err) {
+                    console.error('Database query error:', err);
+                    reject(err);
+                } else {
+                    resolve(rows);
+                }
+            });
+        } else {
+            db.run(sql, params, function(err) {
+                if (err) {
+                    console.error('Database execution error:', err);
+                    reject(err);
+                } else {
+                    // Normalize result to look like MySQL result
+                    // this.lastID, this.changes
+                    resolve({
+                        insertId: this.lastID,
+                        affectedRows: this.changes,
+                        warningStatus: 0
+                    });
+                }
+            });
+        }
+    });
+};
+
+// Mock Pool object for compatibility
+const pool = {
+    query: query,
+    execute: (sql, params) => query(sql, params).then(res => [res]), // Wrap in array for mysql2 compatibility
+    getConnection: () => Promise.resolve({
+        release: () => {},
+        query: query,
+        execute: (sql, params) => query(sql, params).then(res => [res]),
+        beginTransaction: () => query('BEGIN TRANSACTION'),
+        commit: () => query('COMMIT'),
+        rollback: () => query('ROLLBACK')
+    })
 };
 
-// 测试连接
 const testConnection = async () => {
     try {
-        const connection = await pool.getConnection();
-        console.log('数据库连接成功');
-        connection.release();
+        await query('SELECT 1');
+        console.log('SQLite 数据库连接成功');
         return true;
     } catch (error) {
-        console.error('数据库连接失败:', error.message);
+        console.error('SQLite 数据库连接失败:', error.message);
         return false;
     }
 };
@@ -39,4 +67,4 @@ module.exports = {
     pool,
     query,
     testConnection
-};
+};