node.js结合edge连接sqlserver数据库读取数据并显示

原文：http://tech.pro/tutorial/1852/how-to-leverage-sql-server-with-nodejs-using-edgejs（How to leverage SQL Server with Node.js using
Edge.js）

注意连接字符串的处理，文章中这样说道：

Configure your connection string

Before you can use Edge.js with SQL Server, you must set an environment variable named

EDGE_SQL_CONNECTION_STRING

to
a valid ADO.NET connection string. For example:

> set EDGE_SQL_CONNECTION_STRING=Data Source=localhost;Initial Catalog=node-test;Integrated Security=True

EDGE_SQL_CONNECTION_STRING是全局环境变量，用于指定连接的数据库字符串

Further reading

Edge.js Readme
Edge.js is 32x faster than a cross-process call
Introducing Node.js Tools
for Visual Studio
Access SQL Azure from a Node.js
app...

按照上面文章描述，我们建立一个数据库node-test，然后执行sql语句：

IF EXISTS(SELECT 1 FROM sys.tables WHERE object_id = OBJECT_ID('SampleUsers'))
BEGIN;
    DROP TABLE SampleUsers;
END;
GO

CREATE TABLE SampleUsers (
    Id INTEGER NOT NULL IDENTITY(1, 1),
    FirstName VARCHAR(255) NOT NULL,
    LastName VARCHAR(255) NOT NULL,
    Email VARCHAR(255) NOT NULL,
    CreateDate  VARCHAR(20)--DATETIME NOT NULL DEFAULT(getdate()),
    PRIMARY KEY (Id)
);
GO

INSERT INTO SampleUsers(FirstName,LastName,Email,CreateDate) VALUES('Orla','Sweeney','nunc@convallisincursus.ca','Apr 13, 2013');
INSERT INTO SampleUsers(FirstName,LastName,Email,CreateDate) VALUES('Zia','Pickett','porttitor.tellus.non@Duis.com','Aug 31, 2013');
INSERT INTO SampleUsers(FirstName,LastName,Email,CreateDate) VALUES('Justina','Ayala','neque.tellus.imperdiet@temporestac.com','Jul 28, 2013');
INSERT INTO SampleUsers(FirstName,LastName,Email,CreateDate) VALUES('Levi','Parrish','adipiscing.elit@velarcueu.com','Jun 21, 2013');
INSERT INTO SampleUsers(FirstName,LastName,Email,CreateDate) VALUES('Pearl','Warren','In@dignissimpharetra.org','Mar 3, 2013');
INSERT INTO SampleUsers(FirstName,LastName,Email,CreateDate) VALUES('Rinah','Compton','egestas@feliseget.ca','Oct 24, 2013');
INSERT INTO SampleUsers(FirstName,LastName,Email,CreateDate) VALUES('Hasad','Shepherd','fermentum.metus@velit.com','Sep 15, 2013');
INSERT INTO SampleUsers(FirstName,LastName,Email,CreateDate) VALUES('Noelani','Hill','lacus@non.org','Jun 6, 2013');
INSERT INTO SampleUsers(FirstName,LastName,Email,CreateDate) VALUES('Nicole','Jacobson','risus@mattis.com','Aug 8, 2013');
INSERT INTO SampleUsers(FirstName,LastName,Email,CreateDate) VALUES('Alika','Acosta','Duis@felis.ca','Nov 23, 2013');

select * from SampleUsers

编写node.js脚本：

var http = require('http');
var edge = require('edge');
var port = process.env.PORT || 8080;

var getTopUsers = edge.func('sql', function () {/*
    SELECT TOP 5 * FROM SampleUsers ORDER BY CreateDate DESC
*/});

function logError(err, res) {
    res.writeHead(200, { 'Content-Type': 'text/plain' });
    res.write("Error: " + err);
    res.end("");
}

http.createServer(function (req, res) {
    res.writeHead(200, { 'Content-Type': 'text/html' });

    getTopUsers(null, function (error, result) {
        if (error) { logError(error, res); return; }
        if (result) {
            res.write("<ul>");
            result.forEach(function(user) {
                res.write("<li>" + user.FirstName + " " + user.LastName + ": " + user.Email + "</li>");
            });
            res.end("</ul>");
        }
        else {
            res.end("No results");
        }
    });
}).listen(port);
console.log("Node server listening on port " + port);

保存为server-sql-query.js（注意，它使用了edge）

打开dos，指定数据库连接字符串，文章中说明有两种写法的（set和SETX【它要大写的】），随便用一个，我用的是set语句：

set EDGE_SQL_CONNECTION_STRING=Data Source=localhost;Initial Catalog=node-test;uid=sa;pwd=Jon123;

然后node命令运行刚刚新建的server-sql-query.js



成功运行便会打印出“node服务器正在监听8080端口”的信息

然后我们在浏览器中输入http://localhost:8080地址便会显示如下结果：



到此结束。

ps：文章中靠近结尾处，作者的指出的一些看法挺好的，一并摘录此处留着研究

Final thoughts

Edge.js appears to be a very promising solution to bridge the gap between Node.js and the world of .NET.

Although .NET code can be executed in-line, I highly recommend managing all .NET code in a separate assembly.
An ORM can make your life much easier. I prefer Micro-ORMs that aren't heavy-handed and let me do my own thing. Unfortunately, not many ORMs have adopted async support. AsyncPoco and Insight.Database look
promising, but I have not tried them.
If you use Visual Studio, download and install the Node.js Tools for Visual Studio.
Remember, stay async in .NET as much as possible!
Test, test, test! Profile your application's memory, CPU, and concurrency under load to ensure something isn't going terribly wrong between Node.js and .NET.
If your motivation for using Node.js is concurrency and scalability, or reducing your Microsoft licensing footprint, you may want to consider benchmarking Edge.js against a message queue architecture.
Take a look at using RabbitMQ or ZeroMQbetween your
Node.js and Windows environments. A message-based architecture has many benefits. Use the solution that works best for you.
Your mileage may vary.
Just because you can, doesn't mean you should.
Consume copious amounts of caffeine and bacon.

其中说道基于edge.js的消息队列2个项目，挺好的。