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什么是Mongoose?

\r\n
Mongoose是基于node-mongodb-native开发的MongoDB nodejs驱动，可以在异步的环境下执行。\r\n

\r\n
如何安装Mongoose?
\r\n

\r\n

npm install mongoose

\r\n
\r\n

如何使用Mongoose?

\r\n

test.js代码：

\r\n

var mongoose = require('mongoose')\r\n
  , Schema = mongoose.Schema\r\n
\r\n
mongoose.connect('mongodb://localhost/test');\r\n
\r\n
var TestSchema = new Schema({\r\n
   user_id        : {type : Number, index : true}\r\n
  ,username       : {type : String}\r\n
});\r\n
\r\n
var model_name = coll_name = 'taobao';\r\n
mongoose.model(model_name, TestSchema, coll_name);\r\n
\r\n
var TAOBAO  = mongoose.model(model_name, coll_name);\r\n
var taobao  = new TAOBAO();\r\n
taobao.user_id  = 1;\r\n
taobao.username = 'xuanhou';\r\n
taobao.save(function(err) {\r\n
  if (err) {\r\n
    console.log('save failed');\r\n
  }\r\n
  console.log('save success');\r\n
});

\r\n

执行test.js

\r\n
node test.js\r\n

查看是否执行成功：

\r\n

[xuanhou.ysh[@XXXX](/user/XXXX) test]$ mongo\r\n
MongoDB shell version: 1.8.0\r\n
connecting to: test\r\n
> show collections\r\n
system.indexes\r\n
taobao\r\n
> db.taobao.find()\r\n
{ \"_id\" : ObjectId(\"4db65fafcb4312401d000001\"), \"user_id\" : 1, \"username\" : \"xuanhou\" }\r\n
> exit\r\n
bye

\r\n

为什么还要基于node-mongodb-native开发mongoose呢？

\r\n
下面是node-mongodb-native实现的代码相信能让你了解为什么很多人选择Mongoose（callback层数太多）:\r\n

\r\n
\r\n
var client = new Db('integration_tests_20', new Server(\"127.0.0.1\", 27017, {}));\r\n
  client.open(function(err, p_client) {\r\n
        client.createCollection('test_insert', function(err, collection) {\r\n
          client.collection('test_insert', function(err, collection) {\r\n
            for(var i = 1; i < 1000; i++) {\r\n
              collection.insert({c:1}, function(err, docs) {});\r\n
            }\r\n
\r\n
            collection.insert({a:2}, function(err, docs) {\r\n
              collection.insert({a:3}, function(err, docs) {\r\n
                collection.count(function(err, count) {\r\n
                  test.assertEquals(1001, count);\r\n
                  // Locate all the entries using find\r\n
                  collection.find(function(err, cursor) {\r\n
                    cursor.toArray(function(err, results) {\r\n
                      test.assertEquals(1001, results.length);\r\n
                      test.assertTrue(results[0] != null);\r\n
\r\n
                      // Let's close the db\r\n
                      client.close();\r\n
                    });\r\n
                  });\r\n
                });\r\n
              });\r\n
            });\r\n
          });\r\n
        });\r\n
  });\r\n

\r\n

目前Mongoose的开发情况如何？

\r\n
Mongoose已经实现了大部分功能，但还有些Mongodb提供的feature没有实现，所以也给使用者提供了打补丁的机会，下面是我最近给Mongoose打的两个补丁：\r\n

让mongoose支持distinct操作

\r\n

Index: model.js\r\n
===================================================================\r\n
--- model.js    (revision 12218)\r\n
+++ model.js    (working copy)\r\n
@@ -492,6 +492,34 @@\r\n
};\r\n
\r\n
/**\r\n
+ * `distinct` values for key\r\n
+ *\r\n
+ * [@param](/user/param) {String} key\r\n
+ * [@param](/user/param) {Object} conditions\r\n
+ * [@param](/user/param) {Function} optional callback\r\n
+ * [@api](/user/api) public\r\n
+ */\r\n
+\r\n
+Model.distinct = function (key, conditions, callback) {\r\n
+  if ('function' == typeof conditions) {\r\n
+    callback = conditions;\r\n
+    conditions = {};\r\n
+  }\r\n
+  var query = new Query(conditions, key).bind(this, 'distinct');\r\n
+  if ('undefined' == typeof callback)\r\n
+    return query;\r\n
+  var cQuery;\r\n
+  if (cQuery = this._cumulativeQuery) {\r\n
+    merge(query._conditions, cQuery._conditions);\r\n
+    if (query.options && cQuery.options)\r\n
+      merge(query.options, cQuery.options);\r\n
+    delete this._cumulativeQuery;\r\n
+  }\r\n
+  if (!query.model) query.bind(this, 'distinct');\r\n
+  return query.distinct(callback);\r\n
+};\r\n
+\r\n
+/**\r\n
* `where` enables a very nice sugary api for doing your queries.\r\n
* For example, instead of writing:\r\n
*     User.find({age: {$gte: 21, $lte: 65}}, callback);

\r\n

Index: query.js\r\n
===================================================================\r\n
--- query.js    (revision 12218)\r\n
+++ query.js    (working copy)\r\n
@@ -11,6 +11,10 @@\r\n
\r\n
function Query (criteria, options) {\r\n
options = this.options = options || {};\r\n
+  if ('string' == typeof options) {\r\n
+    this._key = options;\r\n
+    options = this.options = {};\r\n
+  }\r\n
this.safe = options.safe\r\n
this._conditions = {};\r\n
if (criteria) this.find(criteria);\r\n
@@ -730,6 +734,24 @@\r\n
};\r\n
\r\n
/**\r\n
+ * Casts this._conditions and sends a distinct\r\n
+ * command to mongodb. Invokes a callback upon\r\n
+ * receiving results.\r\n
+ *\r\n
+ * [@param](/user/param) {Function} callback fn(err, cardinality)\r\n
+ * [@api](/user/api) public\r\n
+ */\r\n
+Query.prototype.distinct = function (callback) {\r\n
+  this.op = 'distinct';\r\n
+  var model = this.model;\r\n
+  this.cast(model);\r\n
+  var castQuery = this._conditions;\r\n
+  var key = this._key;\r\n
+  model.collection.distinct(key, castQuery, callback);\r\n
+  return this;\r\n
+};\r\n
+\r\n
+/**\r\n
* Casts the query, sends the update command to mongodb.\r\n
* If there is an error, the callback handles it. Otherwise,\r\n
* we just invoke the callback whereout passing it an error.

\r\n

让$gt/$gte/$lt/$lte等操作支持字符串参数

\r\n

Index: string.js\r\n
===================================================================\r\n
--- string.js    (revision 12218)\r\n
+++ string.js    (working copy)\r\n
@@ -139,10 +139,15 @@\r\n
}\r\n
\r\n
SchemaString.prototype.$conditionalHandlers = {\r\n
-    '$ne': handleSingle\r\n
+    '$lt': handleSingle\r\n
+  , '$lte': handleSingle\r\n
+  , '$gt': handleSingle\r\n
+  , '$gte': handleSingle\r\n
+  , '$ne': handleSingle\r\n
, '$in': handleArray\r\n
, '$nin': handleArray\r\n
};\r\n
+\r\n
SchemaString.prototype.castForQuery = function ($conditional, val) {\r\n
var handler;\r\n
if (arguments.length === 2) {

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