Share detailed examples of using MongoDB in .Net

I have been studying mongodb recently, and after searching on the Internet, I found that articles about using mongodb in .net are either early driver versions, or there is very little information, so I wrote an essay to record it. This article introduces to you in detail how to use mongodb in .Net. Friends who need a tutorial on how to use MongoDB can refer to it. Let’s take a look below.

What is MongoDB

MongoDB is based on document storage (not tables), and is between a relational database and a non-relational database The products among them are the most feature-rich among non-relational databases and most similar to relational databases. The data structure it supports is very loose and is a bson format similar to json, so it can store more complex data types. The biggest feature of Mongo is that the query language it supports is very powerful. Its syntax is somewhat similar to an object-oriented query language. It can almost implement most functions similar to single-table queries in relational databases, and it also supports indexing of data. Mongo mainly solves the problem of access efficiency of massive data. Because Mongo mainly supports massive data storage, Mongo also comes with an excellent distributed file system, GridFS, which can support massive data storage. Mongo is very popular because it can support complex data structures and has powerful data query functions.

BSON is the data storage format of MongoDB. Everyone is familiar with JSON, but what is BSON? BSON is based on the JSON format. The main reason for choosing JSON for transformation is the versatility of JSON and the schemaless characteristics of JSON.

BSON has the following characteristics

1. Faster traversal speed

For JSON format Generally speaking, a JSON structure that is too large will cause data traversal to be very slow. In JSON, if you want to skip a document for data reading, you need to scan the document and perform troublesome data structure matching, such as bracket matching. A major improvement of BSON to JSON is that it will The length of each element is stored in the header of the element, so that you only need to read the length of the element to directly seek to the specified point for reading.

2. Easier operation

For JSON, data storage is untyped. For example, if you want to modify a basic value from 9 to 10, because from One character becomes two, so all the content after it may need to be moved back one position. Using BSON, you can specify this column as a numeric column. Then, no matter the number grows from 9 to 10 or 100, we will only modify the bit where the number is stored, which will not cause the total length of the data to become larger. Of course, in MongoDB, if the number increases from integer to long integer, the total data length will still increase.

3. Added additional data types

JSON is a very convenient data exchange format, but its types are relatively limited. BSON adds the "byte array" data type on its basis. This eliminates the need to convert binary data to base64 before saving it to JSON. Computational overhead and data size are greatly reduced. Of course, sometimes, BSON does not have a space advantage over JSON because of the type concept.

MongoDB installation under windows

The installation of MongoDB is very simple. After setting the installation path, keep Next until the installation is completed. The biggest pitfall is For the installation of MongoDB service, let’s talk about some configuration operations after MongoDB installation in detail

1. Create the database path (data directory), log path (logs directory), and log file (mongo.log file) in the root directory ), configuration path (conf directory) My installation path is: D:\Program Files\mongodb

2. Create the configuration file mongo.conf in the conf directory, the file content is as follows:

logpath=D:\Program Files\mongodb\logs\mongodb.log #日志输出文件路径

logappend=true #错误日志采用追加模式，配置这个选项后mongodb的日志会追加到现有的日志文件，而不是从新创建一个新文件

journal=true #启用日志文件，默认启用

quiet=true #这个选项可以过滤掉一些无用的日志信息，若需要调试使用请设置为false

port=27017 #端口号 默认为27017

auth=true #启用验证 需要用户名密码

After completing the above 2 steps of configuration, you can start MongoDB

Run CMD input command (note the path of mongod)

mongod --config " D:\Program Files\mongodb\data \conf\mongo.conf"

3. Create and start the MongoDB service

If every Isn’t it quite troublesome to follow step three every time? Follow the following command to create and start the MongoDB service, and then you can manage the startup and shutdown of MongoDB through the windows service

mongod --config " D:\Program Files\mongodb\data \conf\mongo.conf" --install --serviceName "MongoDB"

net start MongoDB

To test whether it is successful, you can enter http://localhost:27017/ in the browser. If the following picture appears, the service installation is successful.

If you need to uninstall the MongoDB service in CMD Run

mongod.exe --remove --serviceName "MongoDB"

After the preliminary preparation work is completed, you can start coding

How to use MongoDB in .net

First introduce MongoDB.Bson.dll, MongoDB.Driver.dll, MongoDB.Driver.Core.dll into the project. I am using version 2.0. Now many articles introduce the use of 1+ This is also the purpose of writing this article. After introducing the driver DLL, you can start coding.

Part of the code is as follows

private static MongoClient client;

private static IMongoDatabase database;

//本地配置

private const string MongoDBConnectionStr = "mongodb://localhost";

//数据库名称

private static string DefaultDataBaseName = "Test";

 

 

public MongoDBHelper()

{

 GetConnection(DefaultDataBaseName);

}

 

/// <summary>

/// 构造函数 指定数据库

/// </summary>

/// <param name="dataBaseName"></param>

public MongoDBHelper(string dataBaseName)

{

 GetConnection(dataBaseName);

}

 
private static void GetConnection(string dataBaseName)

{

 client = new MongoClient(MongoDBConnectionStr);

 database = client.GetDatabase(dataBaseName);

}

/// <summary>

/// 异步插入一条数据，手动输入collection name

/// </summary>

public Task InsertAsync<T>(string collectionName, T obj)

{
 if (database == null)

 {

  throw new Exception("没有指定数据库");

 }

 var collection = database.GetCollection<T>(collectionName);

 return collection.InsertOneAsync(obj);

}

 

/// <summary>

/// 异步插入一条数据，采用类型T的完全限定名作为collection name

/// </summary>

public Task InsertAsync<T>(T obj)

{

 return InsertAsync(typeof(T).FullName, obj);

}

 
/// <summary>

/// 异步插入多条数据，手动输入collection name

/// </summary>

public Task BatchInsertAsync<T>(string collectionName, IEnumerable<T> objs)

{

 if (database == null)

 {

  throw new Exception("没有指定数据库");

 }

 if (objs == null)

 {

  throw new ArgumentException();

 }

 var collection = database.GetCollection<T>(collectionName);

 return collection.InsertManyAsync(objs);

}

 

/// <summary>

/// 异步插入多条数据，采用类型T的完全限定名作为collection name

/// </summary>

public Task BatchInsertAsync<T>(IEnumerable<T> objs)

{

 return BatchInsertAsync(typeof(T).FullName, objs);

}

 

/// <summary>

/// 插入一条数据

/// </summary>

public void Insert<T>(T obj)

{

 InsertAsync(obj).Wait();

}

 

/// <summary>

/// 插入多条数据

/// </summary>

public void Insert<T>(IEnumerable<T> objs)

{

 BatchInsertAsync(objs).Wait();

}

/// <summary>

/// MongoDB C# Driver的Find方法，返回IFindFluent。手动输入collection name

/// </summary>

public IFindFluent<T, T> Find<T>(string collectionName, FilterDefinition<T> filter, FindOptions options = null)

{

 if (database == null)

 {
  throw new Exception("没有指定数据库");

 }
 var collection = database.GetCollection<T>(collectionName);

 return collection.Find(filter, options);

}

/// <summary>

/// MongoDB C# Driver的Find方法，返回IFindFluent。采用类型T的完全限定名作为collection name

/// </summary>

public IFindFluent<T, T> Find<T>(FilterDefinition<T> filter, FindOptions options = null)

{

 return Find(typeof(T).FullName, filter, options);

}
/// <summary>

/// 取符合条件的数据 sort中多个排序条件逗号分隔，默认asc

/// </summary>

public List<T> Get<T>(Expression<Func<T, bool>> condition, int skip, int limit, string sort)

{

 return Get(new List<Expression<Func<T, bool>>> { condition }, skip, limit, sort);

}

public List<T> Get<T>(Expression<Func<T, bool>> condition)

{
 return Get(condition, 0, 0, null);

}

/// <summary>

/// 取符合条件的数据 sort中多个排序条件逗号分隔，默认asc

/// </summary>

public List<T> Get<T>(List<Expression<Func<T, bool>>> conditions, int skip, int limit, string sort)

{

 if (conditions == null || conditions.Count == 0)

 {

  conditions = new List<Expression<Func<T, bool>>> { x => true };

 }

 var builder = Builders<T>.Filter;

 var filter = builder.And(conditions.Select(x => builder.Where(x)));

 var ret = new List<T>();

 try

 {

  List<SortDefinition<T>> sortDefList = new List<SortDefinition<T>>();

  if (sort != null)

  {

   var sortList = sort.Split(&#39;,&#39;);

   for (var i = 0; i < sortList.Length; i++)

   {
    var sl = Regex.Replace(sortList[i].Trim(), @"\s+", " ").Split(&#39; &#39;);

    if (sl.Length == 1 || (sl.Length >= 2 && sl[1].ToLower() == "asc"))

    {

     sortDefList.Add(Builders<T>.Sort.Ascending(sl[0]));

    }

    else if (sl.Length >= 2 && sl[1].ToLower() == "desc")

    {

     sortDefList.Add(Builders<T>.Sort.Descending(sl[0]));
    }

   }
  }

  var sortDef = Builders<T>.Sort.Combine(sortDefList);

  ret = Find(filter).Sort(sortDef).Skip(skip).Limit(limit).ToListAsync().Result;

 }

 catch (Exception e)

 {

  //异常处理

 }

 return ret;

}

public List<T> Get<T>(List<Expression<Func<T, bool>>> conditions)

{

 return Get(conditions, 0, 0, null);

}

In the sample code, only insertion is implemented and query function, the complete code will be uploaded later

Summary

This article only records the most basic usage of MongoDB. Later, we will introduce the copy level, master-slave automatic backup and other mechanisms. and implementation methods.

【Related Recommendations】

1. ASP.NET Free Video Tutorial

2. Getting Started Examples of Python Using MONGODB

3. How to use Python to operate MongoDB database PyMongo library

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