这个和koa没什么关系，npm搜mysql模块即可

写过一些demo，用的是 bookshelf（看了很多mysql orm 之后觉得这个相对来说好用点） 封装了一下数据库表操作 Table

const path = require('path'),
      Helper = require('./helper')
let getTable = ()=> {
  return Helper.walk(path.dirname(__dirname) + '/app/models', 1).reduce((result, item)=> {
    let modelName = path.basename(item, '.js')
    modelName = modelName.split('_').map((item)=> {
      return item[0].toUpperCase() + item.substring(1)
    }).join('')
    result[modelName] = require(item)
    return result
  }, {})
}
module.exports = getTable()

然后就可以往app/models下面扔模型了，下面是会有模型 mem.js

const DB = require('../../lib/db')

module.exports = DB.bookshelf.Model.extend({
  tableName: 'mem',
  constructor: function() {
    DB.bookshelf.Model.apply(this, arguments);
    this.avatar = this.avatar || 'http://awesomes.img-cn-beijing.aliyuncs.com/mem/151014235057-52.jpg'
  }
})

最后在congtroller中调用

exports.post_signup = async (ctx, next) =>{
  let body = ctx.request.body

  let crypto = require('crypto');
  let pwd = crypto.createHash('md5').update(body.pwd).digest('hex');

  
  let param = {
    nc: body.nc,
    pwd: pwd,
    email: body.email
  }

  await new Table.Mem(param).save()
  ctx.body = {status: true}

}

此外还可以构建一些 migration

如 20160616125841_create_table_mem.js

table File  16 lines (11 sloc)  303 Bytes
const knex = require('knex')

exports.up = function(knex, Promise) {
  return knex.schema.createTable('mem', function(table) {
    table.increments('id').primary();
    table.string('email');
    table.string('pwd');
    table.string('nc', 100);
  })
};

exports.down = function(knex, Promise) {
  
};

@DevinXian 谢啦