如何使用 Node 从单个连接/事务进行多个数据库调用.js而且繁琐

您正在尝试在未建立的连接上执行语句。在调用 executeStatement 之前缺少错误处理程序。

connection.on('connect', function (err) {
    if (err) {
        console.log(err); // replace with your code
        return;
    };
    // If no error, then good to go...
    executeStatement();
});

编辑：

如何在串行事务中执行多个语句：

var statements = ["select 1", "select 2", "select 3"];
var transaction = new sql.Transaction(connection);
transaction.begin(function(err) {
    // ... error checks
    async.mapSeries(statements, function(statement, next) {
        var request = new sql.Request(transaction);
        request.query(statement, next);
    }, function(err, results) {
        // ... error checks
        transaction.commit(function(err, recordset) {
            // ... error checks
            console.log("Transaction commited.");
        });
    });
});

您应该使用繁琐的连接池来创建包含多个连接的池。对于节点 js，npm 模块位于： https://www.npmjs.com/package/tedious-connection-pool

对于 for 循环中的每个新值，您可以获取一个新连接并在doneInProc事件上使用connection.reset。您一直在做的情况是正确执行 for 循环的第一次迭代（LoggedIn State），并且由于您继续没有关闭或释放连接，您正在使用相同的连接对象 （ SentClientRequest state ）。因此，当代码达到 for 循环的第二次迭代时，同一对象处于最终状态。希望它能解决您的问题

您可以使用乏味的连接池 https://github.com/pekim/tedious-connection-pool

正如@zevsuld和@mannutech所说，乏味的连接池将启用多个连接，并防止在同时请求进入服务器时出错。

下面是一个通用示例，允许您在一个连接池中编写多个查询，并公开它们以在 API 中使用。我只是添加这个，以防其他人试图完成这种类型的实现。

const ConnectionPool = require('tedious-connection-pool');
const path = require('path');
require('dotenv').config({
  path: path.join(__dirname, '../../.env')
})
let Request = require('tedious').Request;
let poolConfig = {
  min: 10,
  max: 50,
  log: true
}
let connectionConfig  = {
  userName: process.env.user,
  password: process.env.password,
  server: process.env.server
};
//create the pool
let pool = new ConnectionPool(poolConfig, connectionConfig);
pool.on('error', function(err) {
  console.error(err);
});
// At this point in the code, we have established a connection pool.  If you run node, you'll see it log out all then connections to your database. 
// Let's add some methods which your server might use in fulfilling requests to various endpoints.  
let query1 = (cb, res, query) => {
  // acquire a connection:
  pool.acquire(function(err, connection) {
    if (err) {
      console.error(err);
      return;
    } else {
      // form your query
      let sql_query = `SELECT column1, colum2 from TABLE WHERE column1 LIKE '${query.param}%%' ORDER BY column1 ASC`
      // use the connection as usual:
      request = new Request(sql_query, (err, rowCount) => {
        if (err) {
          console.log(err);
          return;
        } else {
          // console.log('rowCount:', rowCount);
        }
        //release the connection back to the pool when finished
        connection.release();
      });
      let records = [];
      request.on("row", function(columns) {
        let rowArray = [];
        columns.forEach(function(column) {
          rowArray.push(column.value);
        });
        records.push(rowArray);
      });
      request.on("doneInProc", function() {
        cb(records, res);
      });
      // lastly exectue the request on the open connection.
      connection.execSql(request);
    }
  });
};
let query2 = (cb, res, query) => {
  // acquire a connection:
  pool.acquire(function(err, connection) {
    if (err) {
      console.error(err);
      return;
    } else {
      // form your query
      let sql_query = `SELECT column3, colum4 from TABLE2 WHERE column3 LIKE '${query.param}%%' ORDER BY column3 ASC`;
      // use the connection as usual:
      request = new Request(sql_query, (err, rowCount) => {
        if (err) {
          console.log(err);
          return;
        } else {
          // console.log('rowCount:', rowCount);
        }
        //release the connection back to the pool when finished
        connection.release();
      });
      let records = [];
      request.on("row", function(columns) {
        let rowArray = [];
        columns.forEach(function(column) {
          rowArray.push(column.value);
        });
        records.push(rowArray);
      });
      request.on("doneInProc", function() {
        cb(records, res);
      });
      // lastly exectue the request on the open connection.
      connection.execSql(request);
    }
  });
};
// Let's expose these two functions to the rest of your API:
module.exports = {
  query1,
  query2
}