修改bug。新增牛只，超链接

backend/controllers/cattleUserController.js

@@ -0,0 +1,168 @@
+/**
+ * 牛只用途控制器
+ * 处理cattle_user表的CRUD操作
+ */
+
+const { sequelize } = require('../config/database-simple')
+
+class CattleUserController {
+  /**
+   * 获取所有牛只用途
+   */
+  async getAllUsers(req, res) {
+    try {
+      const [users] = await sequelize.query('SELECT * FROM cattle_user ORDER BY id ASC')
+      
+      res.json({
+        success: true,
+        data: users,
+        message: '获取牛只用途列表成功'
+      })
+    } catch (error) {
+      console.error('获取牛只用途列表失败:', error)
+      res.status(500).json({
+        success: false,
+        message: '获取牛只用途列表失败',
+        error: error.message
+      })
+    }
+  }
+
+  /**
+   * 根据ID获取牛只用途
+   */
+  async getUserById(req, res) {
+    try {
+      const { id } = req.params
+      const [users] = await sequelize.query('SELECT * FROM cattle_user WHERE id = ?', [id])
+      
+      if (users.length === 0) {
+        return res.status(404).json({
+          success: false,
+          message: '牛只用途不存在'
+        })
+      }
+
+      res.json({
+        success: true,
+        data: users[0],
+        message: '获取牛只用途成功'
+      })
+    } catch (error) {
+      console.error('获取牛只用途失败:', error)
+      res.status(500).json({
+        success: false,
+        message: '获取牛只用途失败',
+        error: error.message
+      })
+    }
+  }
+
+  /**
+   * 创建牛只用途
+   */
+  async createUser(req, res) {
+    try {
+      const { name, description } = req.body
+
+      if (!name) {
+        return res.status(400).json({
+          success: false,
+          message: '用途名称不能为空'
+        })
+      }
+
+      const [result] = await sequelize.query(
+        'INSERT INTO cattle_user (name, description) VALUES (?, ?)',
+        [name, description || null]
+      )
+
+      res.status(201).json({
+        success: true,
+        data: { id: result.insertId, name, description },
+        message: '创建牛只用途成功'
+      })
+    } catch (error) {
+      console.error('创建牛只用途失败:', error)
+      res.status(500).json({
+        success: false,
+        message: '创建牛只用途失败',
+        error: error.message
+      })
+    }
+  }
+
+  /**
+   * 更新牛只用途
+   */
+  async updateUser(req, res) {
+    try {
+      const { id } = req.params
+      const { name, description } = req.body
+
+      if (!name) {
+        return res.status(400).json({
+          success: false,
+          message: '用途名称不能为空'
+        })
+      }
+
+      const [result] = await sequelize.query(
+        'UPDATE cattle_user SET name = ?, description = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?',
+        [name, description || null, id]
+      )
+
+      if (result.affectedRows === 0) {
+        return res.status(404).json({
+          success: false,
+          message: '牛只用途不存在'
+        })
+      }
+
+      res.json({
+        success: true,
+        data: { id: parseInt(id), name, description },
+        message: '更新牛只用途成功'
+      })
+    } catch (error) {
+      console.error('更新牛只用途失败:', error)
+      res.status(500).json({
+        success: false,
+        message: '更新牛只用途失败',
+        error: error.message
+      })
+    }
+  }
+
+  /**
+   * 删除牛只用途
+   */
+  async deleteUser(req, res) {
+    try {
+      const { id } = req.params
+
+      const [result] = await sequelize.query('DELETE FROM cattle_user WHERE id = ?', [id])
+
+      if (result.affectedRows === 0) {
+        return res.status(404).json({
+          success: false,
+          message: '牛只用途不存在'
+        })
+      }
+
+      res.json({
+        success: true,
+        message: '删除牛只用途成功'
+      })
+    } catch (error) {
+      console.error('删除牛只用途失败:', error)
+      res.status(500).json({
+        success: false,
+        message: '删除牛只用途失败',
+        error: error.message
+      })
+    }
+  }
+}
+
+module.exports = new CattleUserController()