完成错误测试用例

backend/test-db-connection.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+# 测试 ocean 数据库连接（本机执行，会提示输入 sudo 密码）
+set -e
+echo "========== 数据库连接测试 =========="
+echo ""
+echo "1. 连接 MySQL 并选择 ocean 数据库..."
+sudo mysql -e "USE ocean; SELECT 'OK' AS connection_status;" 2>/dev/null && echo "   ✓ 连接成功" || { echo "   ✗ 连接失败"; exit 1; }
+echo ""
+echo "2. 查询表与行数..."
+sudo mysql ocean -e "
+  SELECT 'users' AS \`表\`, COUNT(*) AS \`行数\` FROM users
+  UNION ALL SELECT 'projects', COUNT(*) FROM projects
+  UNION ALL SELECT 'operation_logs', COUNT(*) FROM operation_logs;
+"
+echo ""
+echo "3. 表结构预览 (projects 前 5 列)..."
+sudo mysql ocean -e "DESCRIBE projects;" | head -6
+echo ""
+echo "========== 测试完成 =========="