Nodejs对postgresql基本操作的封装

来源：互联网发布：阿里云ecs适合hdfs吗编辑：程序博客网时间：2024/06/07 10:26

基于nodejs平台对postgresql的增删改查基本操作进行了封装，能满足基本的实际应用，比较复杂的SQL需另外实现。

PG.js文件如下：

var pg = require('pg');var conString = "postgres://username:password@localhost/databasename";var client = new pg.Client(conString);var PG = function(){    console.log("准备向****数据库连接...");};PG.prototype.getConnection = function(){    client.connect(function (err) {        if (err) {            return console.error('could not connect to postgres', err);        }        client.query('SELECT NOW() AS "theTime"', function (err, result) {            if (err) {                return console.error('error running query', err);            }            console.log("hbdfxt数据库连接成功...");        });    });};// 查询函数//@param str 查询语句//@param value 相关值//@param cb 回调函数var clientHelper = function(str,value,cb){    client.query(str,value,function(err,result){        if(err) {            cb("err");        }        else{            if(result.rows != undefined)                cb(result.rows);            else                cb();        }    });}//增//@param tablename 数据表名称//@param fields 更新的字段和值，json格式//@param cb 回调函数PG.prototype.save = function(tablename,fields,cb){    if(!tablename) return;    var str = "insert into "+tablename+"(";    var field = [];    var value = [];    var num = [];    var count = 0;    for(var i in fields){        count++;        field.push(i);        value.push(fields[i]);        num.push("$"+count);    }    str += field.join(",") +") values("+num.join(",")+")";    clientHelper(str,value,cb);};//删除//@param tablename 数据表名称//@param fields 条件字段和值，json格式//@param cb 回调函数PG.prototype.remove = function(tablename,fields,cb){    if(!tablename) return;    var str = "delete from "+tablename+" where ";    var field = [];    var value = [];    var count = 0;    for(var i in fields){        count++;        field.push(i+"=$" +count);        value.push(fields[i]);    }    str += field.join(" and ");    clientHelper(str,value,cb);}//修改//@param tablename 数据表名称//@param fields 更新的字段和值，json格式//@param mainfields 条件字段和值，json格式PG.prototype.update = function(tablename,mainfields,fields,cb){    if(!tablename) return;    var str = "update "+tablename+" set ";    var field = [];    var value = [];    var count = 0;    for(var i in fields){        count++;        field.push(i+"=$"+count);        value.push(fields[i]);    }    str += field.join(",") +" where ";    field = [];    for(var j in mainfields){        count++;        field.push(j+"=$"+count);        value.push(mainfields[j]);    }    str += field.join(" and ");    clientHelper(str,value,cb);}//查询//@param tablename 数据表名称//@param fields 条件字段和值，json格式//@param returnfields 返回字段//@param cb 回调函数PG.prototype.select = function(tablename,fields,returnfields,cb){    if(!tablename) return;    var returnStr = "";    if(returnfields.length == 0)        returnStr = '*';    else        returnStr= returnfields.join(",");    var str = "select "+returnStr+ " from "+tablename+" where ";    var field = [];    var value = [];    var count = 0;    for(var i in fields){        count++;        field.push(i+"=$"+count);        value.push(fields[i]);    }    str += field.join(" and ");    clientHelper(str,value,cb);};module.exports = new PG();

用法很简单，如下：

var pgclient = require('./PG');// 引用上述文件pgclient.getConnection();// 调用上述四个函数即可pgclient.save('userinfo',{'name': admin},cb);<span style="font-family: Arial, Helvetica, sans-serif;">.</span>

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