从零开始学习Node.js系列教程之SQLite3和MongoDB用法分析

本文实例讲述了Node.js中SQLite3和MongoDB的用法。分享给大家供大家参考，具体如下：

setup.js：初始化数据库

var util = require('util');
var async = require('async');  //npm install async
var notesdb = require('./nodesdb-sqlite3');
// var notesdb = require('./notesdb-mongoose');
notesdb.connect(function(error){
  if (error) throw error;
});
notesdb.setup(function(error){
  if (error){
    util.log('ERROR ' + error);
    throw error;
  }
  async.series([  //async.series函数可以控制函数按顺序执行，从而保证最后的函数在所有其他函数完成之后执行
    function(cb){
      notesdb.add("test", "testtest",
      function(error){
        if (error) util.log('ERROR ' + error);
        cb(error);
      });
    }
  ],
    function(error, results){
      if (error) util.log('ERROR ' + error);
      notesdb.disconnect(function(err){});
    }
  );
});

nodesdb-sqlite3.js

SQLite3 是一个轻量级的进程内SQL引擎

它是一个无服务器且无需配置的SQL数据库引擎，仅仅是作为一个独立的库被链接到应用程序上

npm install sqlite3 安装此模块之前先在系统上安装sqlite3库 http://www.sqlite.org/download.html 下载

//数据库接口库
var util = require('util');
var sqlite3 = require('sqlite3');
sqlite3.verbose();
var db = undefined;

exports.connect = function(callback){
  db = new sqlite3.Database("chap06.sqlite3", sqlite3.OPEN_READWRITE | sqlite3.OPEN_CREATE,
    function(err){
      if (err){
        util.log('FAIL on creating database ' + err);
        callback(err);
      } else {
        callback(null);
      }
    });
}
//此处的disconnect函数是空的
exports.disconnect = function(callback){
  callback(null);
}
exports.setup = function(callback){
  db.run("CREATE TABLE IF NOT EXISTS notes " +
    "(ts DATETIME, author VARCHAR(255), note TEXT)",
    function(err){
      if (err){
        util.log('FAIL on creating table ' + err);
        callback(err);
      } else {
        callback(null);
      }
    });
}
exports.emptyNote = {"ts": "", author: "", note: ""};
exports.add = function(author, note, callback){
  db.run("INSERT INTO notes (ts, author, note) " +
    "VALUES (?, ?, ?);",
    [new Date(), author, note],
    function(error){
      if (error){
        util.log('FAIL on add ' + error);
        callback(error);
      } else {
        callback(null);
      }
    });
}

exports.delete = function(ts, callback){
  db.run("DELETE FROM notes WHERE ts = ?;",
    [ts],
    function(err){
      if (err){
        util.log('FAIL to delete ' + err);
        callback(err);
      } else {
        callback(null);
      }
    });
}
exports.edit = function(ts, author, note, callback){
  db.run("UPDATE notes " +
    "SET ts = ?, author = ?, note = ? " +
    "WHERE ts = ?",
    [ts, author, note, ts],
    function(err){
      if (err){
        util.log('FAIL on updating table ' + err);
        callback(err);
      } else {
        callback(null);
      }
    });
}
exports.allNotes = function(callback){
  util.log(' in allnote');
  db.all("SELECT * FROM notes", callback);
}
exports.forAll = function(doEach, done){
  db.each("SELECT * FROM notes", function(err, row){
    if (err){
      util.log('FAIL to retrieve row ' + err);
      done(err, null);
    } else {
      doEach(null, row);
    }
  }, done);
}

exports.findNoteById = function(ts, callback){
  var didOne = false;
  db.each("SELECT * FROM notes WHERE ts = ?",
    [ts],
    function(err, row){
      if (err){
        util.log('FAIL to retrieve row ' + err);
        callback(err, null);
      } else {
        if (!didOne){
          callback(null, row);
          didOne = true;  //保证回调函数只被执行一次
        }
      }
    });
}

notesdb-mongoose.js

MongoDB是nosql数据库的领头羊之一，"可扩展、高性能、开源、面向文档的数据库"，它使用JSON风格的文档。

Mongoose是用于访问MongoDB的模块之一，它是一个对象建模工具，意味着你的程序负责定义模式对象来描述数据，

而Mongoose负责数据到MongoDB的存储。

Mongoose对于Node和MongoDB而言是一个非常强大的对象建模工具，使用嵌入式文档，是一个类型灵活的系统，

适用于字段输入、字段验证、虚拟字段等。

MongoDB在Windows下安装部署 ：http://www.lsjlt.com/article/111112.htm

安装Mongoose模块

npm install mongoose

Mongoose不是唯一一个在node中使用MongoDB的工具。

var util = require('util');
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var dburl = 'mongodb://localhost/chap06'; //dburl用于连接已运行的MongoDB
exports.connect = function(callback){
  mongoose.connect(dburl);
}
exports.disconnect = function(callback){
  mongoose.disconnect(callback);
}
exports.setup = function(callback){callback(null);}
//定义模式
var NoteSchema = new Schema({
  ts: {type: Date, default: Date.now}, //默认值
  author: String,
  note: String
});
//将NoteSchema作为Mongoose的模型注册进去
mongoose.model('Note', NoteSchema);
var Note = mongoose.model('Note');
exports.emptyNote = {"_id": "", author: "", note: ""};
exports.add = function(author, note, callback){
  var newNote = new Note();
  newNote.author = author;
  newNote.note = note;
  newNote.save(function(err){
    if (err){
      util.log('FATAL ' + err);
      callback(err);
    } else {
      callback(null);
    }
  });
}
exports.delete = function(id, callback){
  exports.findNoteById(id, function(err, doc){
    if (err){
      callback(err);
    } else {
      util.log(util.inspect(doc));
      doc.remove();
      callback(null);
    }
  });
}
exports.edit = function(id, author, note, callback){
  exports.findNoteById(id, function(err, doc){
    if (err){
      callback(err);
    } else {
      doc.ts = new Date();
      doc.author = author;
      doc.note = note;
      doc.save(function(err){
        if (err){
          util.log('FATAL ' + err);
          callback(err);
        } else {
          callback(null);
        }
      });
    }
  });
}
exports.allNotes = function(callback){
  Note.find({}, callback);
}
exports.forAll = function(doEach, done){
  Note.find({}, function(err, docs){
    if (err){
      util.log('FATAL ' + err);
      done(err, null);
    }
    docs.forEach(function(doc){
      doEach(null, doc);
    });
    done(null);
  });
}

var findNoteById = exports.findNoteById = function(id, callback){
  Note.findOne({_id: id}, function(err, doc){
    if (err){
      util.log('FATAL ' + err);
      callback(err, null);
    }
    callback(null, doc);
  });
}

app.js

//在数据库需要放置在一台计算机上时，应该考虑使用SQLite3
//控制器，在nodesdb-sqlite3.js和notesdb-mongoose.js模块之间切换
var util = require('util');
var url = require('url');
var express = require('express');
var nmDbEngine = 'sqlite3'; //用于命名数据库引擎、选择合适的notesdb实现和选择合适的views目录
//var nmDbEngine = 'mongoose';
var notesdb = require('./nodesdb-' + nmDbEngine);
var app = express();
app.use(express.logger());
app.use(express.cookieParser()); //添加cookieParser中间件
app.use(express.bodyParser());
app.engine('.html', require('ejs').__express);  //3.X
//app.register('.html', require('ejs'));  //2.X
app.set('views', __dirname + '/views-' + nmDbEngine);
app.set('view engine', 'ejs');
//是一个路由中间件函数，用于在一些路由器函数中解析URL查询参数
var parseUrlParams = function(req, res, next){
  req.urlP = url.parse(req.url, true);
  next();
}
//检查用户是否被允许访问，这里只检查cookie是否等于AOK，这个单词通常意味着一切都没问题

var checkAccess = function(req, res, next){
  if (!req.cookies || !req.cookies.notesaccess || req.cookies.notesaccess !== "AOK"){
    res.redirect('/login');
  } else {
    next();
  }
}
notesdb.connect(function(error){
  if (error) throw error;
})
app.on('close', function(error){
  notesdb.disconnect(function(err){});
});
app.get('/', function(req, res) {res.redirect('/view');});
app.get('/view', checkAccess, function(req, res){ //可以在每个路由上加checkAccess检查
  notesdb.allNotes(function(err, notes){
    if (err){
      util.log('ERROR ' + err);
      throw err;
    } else {
      res.render('viewnotes.html', {title: "Notes ("+ nmDbEngine +")", notes: notes});
    }
  });
});

app.get('/add', function(req, res){
  res.render('addedit.html', {title: "Notes ("+ nmDbEngine +")", postpath: '/add', note: notesdb.emptyNote});
});
app.post('/add', function(req, res){
  notesdb.add(req.body.author, req.body.note,
    function(error){
      if (error) throw error;
      res.redirect('/view');
    });
});
app.get('/del', parseUrlParams, function(req, res){
  notesdb.delete(req.urlP.query.id,
    function(error){
      if (error) throw error;
      res.redirect('/view');
    });
});
app.get('/edit', parseUrlParams, function(req, res){
  notesdb.findNoteById(req.urlP.query.id,
    function(error, note){
      if (error) throw error;
      res.render('addedit.html',
        {title: "Notes ("+ nmDbEngine +")", postpath: '/edit', note: note});
    });
});
app.post('/edit', function(req, res){
  notesdb.edit(req.body.id, req.body.author, req.body.note,
    function(error){
      if (error) throw error;
      res.redirect('/view');
    });
});
app.get('/login', function(req, res){
  res.render('login.html', {title: "Notes LOGIN ("+ nmDbEngine +")"});
});
app.post('/login', function(req, res){
  //此处可以添加检查用户信息的逻辑
  //...
  res.cookie('notesaccess', 'AOK');
  res.redirect('/view');
});
app.listen(3000);

show.js

//控制台显示
var util = require('util');
var notesdb = require('./notesdb-sqlite3');
// var notesdb = require('./notesdb-mongoose');
notesdb.connect(function(error){
  if (error) throw error;
});
notesdb.forAll(function(error, row){
  util.log('ROW: ' + util.inspect(row));
}, function(error){
  if (error) throw error;
  util.log('ALL DONE');
  notesdb.disconnect(function(err){});
});

前台页面在views-sqlite3目录下

layout.html

<!DOCTYPE html>
<html>
<head>
  <title><%= title%></title>
</head>
<body>
  <h1><%= title%></h1>
  <p><a href='/view'>View</a> | <a href='/add'>Add</a></p>
</body>
</html>

viewnotes.html

<% include layout.html %>
<table><% notes.forEach(function(note){ %>
  <tr>
    <td>
      <p><%=new Date(note.ts).toString()%>: by <b><%=note.author%></b></p>
      <p><%=note.note%></p>
    </td>
    <td>
      <form method="get" action="/del">
        <input type="submit" value="Delete" />
        <input type="hidden" name="id" value="<%=note.ts%>" />
      </form>
      <br/>
      <form method="get" action="/edit">
        <input type="submit" value="Edit" />
        <input type="hidden" name="id" value="<%=note.ts%>" />
      </form>
    </td>
  </tr>
  <% }); %>
</table>

addedit.html

<% include layout.html %>
<form method="post" action="<%=postpath%>">
  <% if (note){ %>
  <input type="hidden" name="id" value="<%=note.ts%>" />
  <% } %>
  <input type="text" name="author" value="<%=note.author%>" />
  <br/>
  <textarea rows="5" cols="40" name="note">
    <%=note.note%>
  </textarea>
  <br/>
  <input type="submit" value="Submit" />
</form>

login.html

<% include layout.html %>
<form method="POST" action="/login">
  <p>Click the <i>Login</i> to log in.</p>
  <input type="submit" value="Login" />
</form>

node setup.js

node app.js

希望本文所述对大家nodejs程序设计有所帮助。