node 和 postgres

var pg = require(‘pg‘);

// 数据库配置
var config = {  
    user:"postgres",
    database:"test",
    password:"postgres",
    port:5432,
    // 扩展属性
    max:20, // 连接池最大连接数
    idleTimeoutMillis:3000, // 连接最大空闲时间 3s
}
// 创建连接池
var pool = new pg.Pool(config);
// 查询
pool.connect(function(err, client, done) {  
  if(err) {
    return console.error(‘数据库连接出错‘, err);
  }
  // 简单输出个 Hello World
  client.query(‘SELECT $1::varchar AS OUT‘, ["Hello World"], function(err, result) {
    done();// 释放连接（将其返回给连接池）
    if(err) {
      return console.error(‘查询出错‘, err);
    }
    console.log(result.rows[0].out); //output: Hello World
  });
});

const pg=require(‘pg‘)
var conString = "postgres://username:password@localhost/databaseName";
var client = new pg.Client(conString);
client.connect(function(err) {
    if(err) {
      return console.error(‘连接postgreSQL数据库失败‘, err);
    }
    client.query(‘SELECT * FROM tableName‘, function(err, data) {
      if(err) {
        return console.error(‘查询失败‘, err);
      }else{
        // console.log(‘成功‘,data.rows); 
        console.log(‘成功‘,JSON.stringify(data.rows)); 
      }
      client.end();
    });
  });

// 连接pg
var pg = require(‘pg‘);
var pool = new pg.Pool({
    host: ‘XXXXXX‘,
    user: ‘XXXX‘,
    password: ‘XXXXX‘,
    database: ‘XXX‘,
    port:5432,
    max:20, // 连接池最大连接数
    idleTimeoutMillis:3000, // 连接最大空闲时间 3s
});

function query(sql, callback) {
    pool.connect(function (err, connection,done) {
        if (err) {
            console.log(‘connect query:‘ + err.message);
            return;
        }
        // Use the connection
        connection.query(sql,[],function (err, rows) {
	    done();
            callback(err, rows);
            //connection.release();//释放链接
        });
    });
}
exports.query = query;

/**
     * 获取survey
	 *localhost:5000/getAllSurveyList
     */
    app.get(‘/getAllSurveyList‘, function (req, res) {
        console.log("getAllSurveyList");
        db.query(‘select id,trim(latitude) as latitude,trim(lontitude) as lontitude,isshow as ‘+‘"‘+‘isShow‘+‘"‘+‘ from survey‘, function (err,rows) {	
            if (err) {
				console.log(err);
				console.log(‘--getAllSurveyList: 查询失败‘);
                res.json({result:‘false‘,datas: null});
            } else {
				console.log(‘--getAllSurveyList: 查询成功‘);
				//console.log(rows);
                res.json({result: ‘true‘, datas: rows.rows});
            }
        })
    });

var pg = require(‘./pg‘); //加载模块node-postgres,该模块要与本文件放于同一个目录下
var conString = "postgres://postgres:postgres@localhost:5432/node-test";//此时数据库必须已经创建
                //anything://user:password@host:port/database
var client = new pg.Client(conString);

client.connect(function(err) {
    if(err) {
        return console.error(‘could not connect to postgres‘, err);
    }
     
    //删除存在表
    console.log("Dropping table ‘person‘")
    var query = client.query("drop table if exists person");
    query.on(‘end‘, function() {
        console.log("Dropped!");
    });
     
    //创建表
    console.log("Creating table ‘person‘");
    query = client.query("create table person(id serial, username varchar(10), password varchar(10), age integer)");
    query.on(‘end‘, function(){
        console.log("Created!");
     }); 
    
    //添加
    client.query(‘INSERT INTO person(username, password, age) VALUES($1, $2, $3)‘, ["zhangsan", "123456", 20], function(err, result) {
    console.log( "====================add========================");
    if(err) {
        console.log(err); 
        return rollback(client);
    }
        console.log( result);
    }); 


    //查询
    client.query(‘select username, password, age from person where id = $1‘, [3], function(err, result) {
    console.log( "===================query=========================");
    if(err) {
        console.log(err);  
    }
        console.log(result.rows[0]);
    });

    //更新
    client.query(‘update person set password=$1 where id = $2‘, ["11a",1], function(err, result) {
    console.log( "=====================update=======================");
    if(err) {
        console.log(err);  
    }
        console.log(result);
    });

    //删除
    client.query(‘delete from person where id = $1‘, [1], function(err, result) {
    console.log( "====================remove=======================");
    if(err) {
        console.log(err);  
    }
        console.log(result);
        client.end();
    });
    
});
 
 var rollback = function(client) { 
  client.query(‘ROLLBACK‘, function() {
    client.end();
  });
};