mysql與koa

/**
	* Created by db on 2018/7/20
	*/
	const mysql = require('mysql')
	const defautConfig = {
	host: 'localhost',
	user: 'root',
	password: '',
	database: 'test',
	connectionLimit: 20
	}
	const AsyncMysqljs = function(config=defautConfig){
	const pool = mysql.createPool(config)
	const q = function (sql, values) {
	return new Promise((resolve, reject) => {
	pool.getConnection((err, conn) => {
	if (err) return reject(err)
	conn.query(sql, values, (err, rows) => {
	if (err) reject(err)
	else resolve(rows)
	conn.release()
	})
	})
	})
	}
	/*
	從數據庫中查詢一條數據，返回值是對象，而非數組
	最好在sql語句中加一個唯一的限制條件
	*/
	const get = (sql, values) => {
	try {
	return q(sql, values).then(rows => {
	if (rows.length >= 1) {
	return rows[0]
	}
	})
	} catch (err) {
	return new Promise((resolve, reject) => {
	reject(err)
	})
	}
	}
	return {query: q, delete: q, update: q, insert: q, execute: q, get}
	}
	module.exports = AsyncMysqljs