Question

我正在使用pg作为节点连接到我的Postgres服务器。

这是我在做什么：

const Pool = require('pg').Pool;

var config = {
    user: "mouser",
    password: "my password",
    host: "somethingsomething.rds.amazonaws.com",
    port: 5432,
    database: "mydb",
    ssl: true
}

const db = new Pool(config);

console.log("hello world")

let queryString = `CREATE TABLE IF NOT EXISTS favoritememes (id serial PRIMARY KEY, image_url varchar(255), date_favorited TIMESTAMP DEFAULT CURRENT_TIMESTAMP);`
db.query(queryString, function(err, result) {
    console.log("Created table");
    if (err) console.log("error", err);
});

当前，我在控制台上看到了“ hello world”，但从未打印过“ created table”，也从未看到错误。

我知道我的凭据是正确的，因为我可以使用具有相同凭据的SQLWorkbench连接到服务器。

Answer 1

我认为问题在于您没有等待池完成创建。

另外，我建议使用：

对您的db函数的承诺，它将使您对javascript; D感觉更好。
我建议您使用参数化查询功能。他们帮助保持代码干净，也防止您需要处理变量类型 /逃跑。
（顺便说一句，我将其放在另一个文件中，并通过exports.parameterizedPromise = parameterizedPromise.导出parameterizedPromise

以下是如何使用参数化查询承诺的示例： / *

parameterizedPromise('SELECT * FROM foodtable f WHERE f.flavor = $1 AND f.meal = $2;', ['SPICY', 'BREAKFAST'])
.then(function(result){
  console.log(result.rows);
})
.catch(function(error){
  console.warn(error);
});
*/

这是我前一段时间使用的编辑版本。

 const pg = require('pg');

  const DBConfig = {
      host: 'xxxxxx',
      port: 'xxxxxx',
      user: 'xxxxxx',
      password: 'xxxxxx',
      database: 'xxxxxx',
      max: 10,   // max number of clients in the pool
      ssl: true,
      idleTimeoutMillis: 30000  // how long a client is allowed to remain idle before being closed
  };

  const postgresPool = new pg.Pool(DBConfig, function(){
    console.log('connected to postgres database');

    // Need to wait for the pool to finish connecting before you can fire off your query.
    paramaterizedPromise(`CREATE TABLE IF NOT EXISTS favoritememes (id serial PRIMARY KEY, image_url varchar(255), date_favorited TIMESTAMP DEFAULT CURRENT_TIMESTAMP);`, [])
    .then(function(result){
        console.log(result);
    })
    .catch(function(error){
        console.warn(error);
    });
  });


  postgresPool.on('error', function (err, client) {
    // if an error is encountered by a client while it sits idle in the pool
    // the pool itself will emit an error event with both the error and
    // the client which emitted the original error
    // this is a rare occurrence but can happen if there is a network partition
    // between your application and the database, the database restarts, etc.
    // and so you might want to handle it and at least log it out
    console.error('idle client error', err.message, err.stack);
  });



const paramaterizedPromise = function(query, params) {
  return new Promise( function(resolve, reject){
    postgresPool.connect(function(err, client, done) {
      if(err) {
        reject('Error Fetching Client From Pool', err);
      }
      client.query(query, params, function(err, result) {
        //call `done()` to release the client back to the pool
        done(err);
        if (err){
          reject(err);
        } else {
          resolve(result);
        }
      });
    });
  });
}

pg.query没有调用回调函数

1 个答案: