[node.js学习]为node.js写的一个操作mysql的类

不支持一个对象在不同异步中使用,模仿的php框架 speedphp中的model模块

GaryMysql.js

var mysql = require('mysql');
var pool  = null;
//由于使用了一些类的属性,所以不支持在多线程情况下使用同一对象执行sql
module.exports = class GaryMysql{
    constructor(tabName, pk) { 
        this.tabName = tabName;//类中变量
        this.pk = typeof pk !=="undefined"?pk:'id';
        this.initSet();
    }
    static setDB(host,user,password,database)
    { 
        if(pool==null)
        {
            pool=mysql.createPool({
                      connectionLimit : 10,
                      host            :  host ,
                      user            :  user ,
                      password        :  password ,
                      database        :  database 
                    });
        }
    }
    query(sql,callback){ 
            var values=this.values;
            this.initSet();
            pool.getConnection(function(err,conn){ 
                            if(err){
                                callback(err,null,null);
                            }else{
                                conn.query(sql,values,function(qerr,vals,fields){
                                    //释放连接
                                    conn.release();
                                    //事件驱动回调
                                    callback(qerr,vals,fields);
                                });
                            }
                        });
    }
     
     //strWhere  
    // 链式调用 
    where(whereSet,values)
    {
        this.values = typeof values !=="undefined"?values:[];
        if(typeof whereSet==='string')
        {
            this.strWhere=whereSet;
        }else if(typeof whereSet==='object')
        {
            var strWhere='';
            for(var key in whereSet)
            {
                if(strWhere!='')strWhere+=' AND '; 
                strWhere+=key+'=?';
                this.values.push(whereSet[key]) ;  
            }
            this.strWhere=strWhere;
        }else{
            this.strWhere='';
        }
        if(this.strWhere!="")this.strWhere=" WHERE "+this.strWhere
         
        return this;
    } 
     
     
    findCont(callback){  
        var sql='SELECT COUNT(1)C FROM '+this.tabName+this.strWhere; 
        this.query(sql,function(err, result){
            if(!err)
            {
                 result=result[0].C;
            }
            if(typeof callback =="function")
            {
                callback(err,result);
            } 
        }); 
    }
    find(callback,order,field)
    { 
    
        this.findAll(function(err,rows,fields){
             if(typeof callback =="function")
             {
                rows=rows&&rows.length>0?rows[0]:null;
                callback(err,rows,fields);
             }
        },order,field,1);
    }
    findAll(callback,order,field,limit){  
        order = typeof order !=="undefined"?' ORDER BY '+order:'';
        field = typeof field !=="undefined"?field:'*';
        limit = typeof limit !=="undefined"?' LIMIT '+limit:''; 
        
        var sql='SELECT '+field+' FROM '+this.tabName+this.strWhere+order+limit; 
        this.query(sql,function(err,rows,fields){
            if(typeof callback =="function")
             {
                rows=rows&&rows.length>0?rows:null;
                callback(err,rows,fields);
             }
        });  
    }
    
    //setData 需要在 setWhere前面
    data(dataSet){
        this.dataStr='';
        this.values = typeof values !=="undefined"?values:[];
        for(var key in dataSet)
        {
            if(this.dataStr!='')this.dataStr+=','; 
            this.dataStr+=key+'=?';
            this.values.push(dataSet[key]) ;
        }
        return this;
    }
    del(callback){
        
        var sql='DELETE FROM '+this.tabName+this.strWhere;   
        this.query(sql,function(err,result,fields){
             if(typeof callback =="function")
             {
                 if(!err)
                 {
                      result=result.affectedRows;
                 }
                 callback(err,result,fields);
             }
        }); 
    }
    update(callback){  
        var sql='UPDATE '+this.tabName+' SET '+this.dataStr+this.strWhere;   
        this.query(sql,function(err,result,fields){
             if(typeof callback =="function")
             {
                 if(!err)
                 {
                     result=result.changedRows;
                 }
                 callback(err,result,fields);
             }
        }); 
    }
    //
    create(dataSet,callback)
    { 
        var fields="";
        var valuesStr=""; 
        for(var key in dataSet)
        {
            if(fields!="")fields+=",";
            if(valuesStr!="")valuesStr+=",";
            fields+=key;
            valuesStr+="?";
            this.values.push(dataSet[key]) ;
        }
        
        var sql="INSERT INTO "+this.tabName+"("+fields+")VALUES("+valuesStr+")"; 
        this.query(sql,function(err,result,fields){
             if(typeof callback =="function")
             {
                 if(!err)
                 {
                     result=result.insertId;
                 }
                 callback(err,result,fields);
             }
        });
    }
 
    initSet(){
        this.values=[];
        this.dataStr='';
        this.strWhere='';
    } 
} 

使用

var GaryMysql = require('./GaryMysql');
GaryMysql.setDB('localhost','root','root','msg');
var m_main=new GaryMysql('m_main'); 
m_main.where({"txt":"1223"}).find(function(err,result,fields){
        if(err)
        {
            console.log(err);
        } 
        console.log(result); 
    });
    
 m_main.where({"txt":"1223"}).findAll(function(err,result,fields){
        if(err)
        {
            console.log(err);
        } 
        console.log(result); 
    });
//实际不能直接这样一个对像使用两次,只有在回调里面才可以,最好是重新new一个,或者在回调中使用,