从NodeJs连接SQL数据库-ConnectionError:连接尚未打开

connection pool 类将返回一个承诺,该承诺与连接启动的池进行解析:

 var executeQuery = function(res, query) { 

     var conn = new sql.ConnectionPool(dbConfig);

     conn.connect()
         .then(function (pool) {
             //    ^ the pool that is created and should be used

             // create Request object
             var request = new sql.Request(pool);
             //                            ^ the pool from the promise

             // query to the database
             request.query(query, function (err, queryResult) {
                 if (err) {
                     console.log("Error while querying database :- " + err);
                     res.send(err);
                 } else {
                     res.send(queryResult);
                 }
             });
             conn.close();
        });           
}

conn 变量始终是承诺,而不是连接本身。

new sql.ConnectionPool(config).connect().then(pool => {
    return pool.query`select * from mytable where id = ${value}`
}).then(result => {
    console.dir(result)
}).catch(err => {
    // ... error checks
})