node and postgres

Install npm i pg, if slow, remember to climb a ladder

Connection Pooling way:

the require PG = var ( 'PG'); 

// database configuration 
var config = {   
    User: "Postgres", 
    Database: "Test", 
    password: "Postgres", 
    Port: 5432, 
    // extended attribute 
    max: 20, // The maximum number of connection pools 
    idleTimeoutMillis: 3000, // the maximum idle time is connected 3S 
} 
// create a connection pool 
var = new new pg.Pool the pool (config); 
// query 
pool.connect (function (ERR, Client, DONE) {   
  IF (ERR) { 
    return console.error ( 'error database connection', ERR); 
  } 
  // output a simple World the Hello 
  client.query ( '$ the SELECT OUT. 1 :: VARCHAR the AS', [ "the Hello World"], function (ERR , Result) { 
    DONE ();// releasable connection (which is returned to the pool) 
    IF (ERR) { 
      return console.error ( 'Query Error', err); 
    }
    console.log(result.rows[0].out); //output: Hello World
  });
});

Client direct connection:

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();
    });
  });

One way to find their own way:

// Connect PG 
var PG = the require ( 'PG'); 
var the pool = new new ({pg.Pool 
    Host: 'XXXXXX', 
    User: 'XXXX', 
    password: 'xxxxx', 
    Database: 'XXX', 
    Port: 5432 , 
    max: 20 is, // the maximum number of connections the connection pool 
    idleTimeoutMillis: 3000, // the maximum idle time is connected 3S 
}); 

function Query (SQL, the callback) { 
    pool.connect (function (ERR, connection, DONE) { 
        IF (ERR ) { 
            the console.log ( 'Connect Query:' + err.message); 
            return; 
        } 
        // the Use Connection The 
        connection.query (SQL, [], function (ERR, rows) { 
	    DONE (); 
            the callback (ERR, rows );
            //connection.release();// release link // release link 
        });
    }); 
} 
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});
            }
        })
    });

CRUD

var pg = require ( './ pg '); // load module node-postgres, the module to be placed in this document in the same directory 
var conString = "postgres: // postgres : postgres @ localhost: 5432 / node- test "; // when the database must be created 
                // Anything: // User: password @ Host: Port / database 
var = new new Client pg.Client (conString); 

the client.connect (function (ERR) { 
    IF (ERR) { 
        return console.error ( 'Could Not Connect to Postgres', ERR); 
    } 
     
    // delete the table exists 
    the console.log ( "Dropping table 'Person'") 
    var = client.query Query ( "drop Person table IF eXISTS") ; 
    query.on ( 'End', function () { 
        the console.log () "the Dropped!"; 
    }); 
     
    // Create a table 
    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();
  });
};