此封装适合于使用 SQL 直接操作数据库的小型后端项目，更多功能请查阅MySQL2官网
// 代码保存到单独的 js 文件const mysql = require('mysql2/promise')const debug = true
let conn/*** 执行 SQL 语句* @param {String} sql* @param {*} params* @returns {Array}*/
const query = (sql, params)=> {if(!conn) throw Error(`数据库连接未创建，请配置 useDB、dbName 属性...`)debug && console.debug("[SQL]", sql, "[PARAMS]",Array.isArray(params)?params[0]:(params||"（无）"))return conn.query(sql, params)
}exports.query = query/*** 创建 mysql 连接（使用连接池）* @param {import('.').ServerConfig} config* @returns*/
exports.mysqlBuilder = async config=> {if(!!conn) returnconn = mysql.createPool({host: config.host || 'localhost',port: config.port || 3306,user: config.user || 'root',password: config.pwd || '',database: config.database,waitForConnections: true,connectionLimit: 10,idleTimeout: 180 * 1000,enableKeepAlive: true,keepAliveInitialDelay: 0})return conn
}/*** 返回指定的sql结果数量* @param {String} table - 表名* @param {String} condition - 条件 SQL* @returns {Number}*/
exports.count = async (table, condition, params) => {let [ results ] = await query(`SELECT COUNT(*) FROM ${table} WHERE ${condition}`, params)return Number(results[0])
}/*** 按 ID 查询数据（单条）* @param {String} id* @param {String} table* @param {String} idField - ID字段名，默认 id* @returns {Object}*/
exports.findById= async (id, table, idField="id")=>{let [ results ] = await query(`SELECT * FROM ${table} WHERE ${idField}=? LIMIT 1`, id)return results[0]
}/*** 保存数据到指定表* @param {Object} obj - 待保存对象（默认取全部的字段，排除_开头）* @param {String} table - 表名* @param {Array<String>} ignores - 忽略的字段* @returns*/
exports.saveObjToTable = async (obj, table, ignores=[])=>{let fields = Object.keys(obj).filter(k=> !(k.startsWith("_") || ignores.includes(k)))let [ results ] = await query(`INSERT INTO ${table} (${fields.join(",")}) VALUES (${fields.map(v=>'?').join(",")})`, fields.map(v=> obj[v]))return results
}/*** 将对象保存到指定数据表* @param {Object} obj - 待保存对象（默认取全部的字段，排除_开头）* @param {String} table - 表名* @param {String} idField - 主键字段名* @param {Array<String>} ignores - 忽略的字段* @returns*/
exports.updateObjToTable = async (obj, table, idField="id", ignores=[])=>{let fields = Object.keys(obj).filter(k=> !(k!=idField, k.startsWith("_") || ignores.includes(k) || obj[k]===undefined))let [ results ] = await query(`UPDATE ${table} set ${fields.map(f=>`${f}=?`).join(",")} WHERE ${idField}=?`,fields.concat(idField).map(v=> obj[v]))return results
}/*** 将对象的某个字段进行 JSON 处理* @param {Object} obj - 待处理对象* @param {Array<String>} fields - 待转换的属性清单* @param {Boolean} toString - 转换为字符串，false=反序列到JSON对象*/
exports.dealJSONField = (obj, fields, toString = true)=> {if(typeof(obj) == 'object'){fields.filter(k=> k in obj).forEach(k=> obj[k] = toString ? JSON.stringify(obj[k]) : JSON.parse(obj[k]))}return obj
}
如何使用
const { mysqlBuilder, query } = require("basic/server/mysql")await mysqlBuilder({ host:"localhost", database:"test", user:"root" })let [ results ] = await query(`这里填写 SQL 语句`)
console.info(results )
// 更多语法请参考官方文档 https://sidorares.github.io/node-mysql2/docs
)
