.Net Core使用MongoDB的詳細教程

更新時間：2020年08月04日 08:41:42 作者：江北的博客、

這篇文章主要給大家介紹了關(guān)于.Net Core使用MongoDB的完整步驟，文中通過示例代碼介紹的非常詳細，對大家的學習或者工作具有一定的參考學習價值，需要的朋友們下面來一起學習學習吧

前言

MongoDB 是由C++語言編寫的，是一個基于分布式且面向文檔存儲的開源數(shù)據(jù)庫系統(tǒng)。

下載地址：

https://www.mongodb.com/download-center/community

在.Net Core中使用需要引入核心包 MongoDB.Driver

添加數(shù)據(jù)：

//與Mongodb建立連接
MongoClient client = new MongoClient("mongodb://127.0.0.1");
//獲得數(shù)據(jù)庫,沒有則自動創(chuàng)建
IMongoDatabase db = client.GetDatabase("db1");
//拿到集合(表)
IMongoCollection<Student> student = db.GetCollection<Student>("Student");
var data = new Student();
data.id = 1;
data.name = "江北";
data.age = 22;
data.remarks = "暫無";
//添加一條數(shù)據(jù)
student.InsertOne(data);

在圖形化界面中查看一下

Mongodb默認用id做主鍵,因此不會顯式的指定id是主鍵。Mongdb中沒有內(nèi)置"自增字段",可以把id聲明為ObjectId類型,這樣插入以后就自動給字段賦值。

例如，建一個類：

public class School
{
 public ObjectId id { get; set; }
 public string name { get; set; }
 public string address { get; set; }
}//需引入命名空間 using MongoDB.Bson;

當然School對象之后多加或者去掉一個字段都行。Mongodb是用Json保存的,因此也可以直接用Json格式插入,可用BsonDocument對象作為泛型對象。

//與Mongodb建立連接
MongoClient client = new MongoClient("mongodb://127.0.0.1");
//獲得數(shù)據(jù)庫,沒有則自動創(chuàng)建
IMongoDatabase db = client.GetDatabase("db1");
//拿到集合(表)
IMongoCollection<BsonDocument> document = db.GetCollection<BsonDocument>("School");
db.GetCollection<BsonDocument>("School");
var json = "{id:1,name:'xx學校',address:'xxx路xx號',remarks:'暫無！'}";
BsonDocument bsons = BsonDocument.Parse(json);

學生和學校是有對應關(guān)系的,我們可以添加有嵌套關(guān)系類型的對象

public class Student
{
 public int id { get; set; }
 public string name { get; set; }
 public int age { get; set; }
 public string remarks { get; set; }
 public School School { get; set; }
}

//與Mongodb建立連接
MongoClient client = new MongoClient("mongodb://127.0.0.1");
//獲得數(shù)據(jù)庫,沒有則自動創(chuàng)建
IMongoDatabase db = client.GetDatabase("db1");
//拿到集合(表)
IMongoCollection<Student> student = db.GetCollection<Student>("Student");
Student student1 = new Student();
student1.id = 2;
student1.name = "北晚舟";
student1.age = 22;
student1.remarks = "暫無";
School school = new School();
school.name = "xxxSchool";
school.address = "xxxAddress";
student1.School = school;
student.InsertOne(student1);

數(shù)據(jù)查詢：

//與Mongodb建立連接
MongoClient client = new MongoClient("mongodb://127.0.0.1");
//獲得數(shù)據(jù)庫,沒有則自動創(chuàng)建
IMongoDatabase db = client.GetDatabase("db1");
//拿到集合(表)
IMongoCollection<Student> student = db.GetCollection<Student>("Student");
var data = Builders<Student>.Filter.Gt(m => m.age, 21);//Gt:大于
var result = student.Find(data).ToList();

我們安裝的NuGet包是支持Lamda表達式的,可用條件表達式來查找數(shù)據(jù)

//與Mongodb建立連接
MongoClient client = new MongoClient("mongodb://127.0.0.1");
//獲得數(shù)據(jù)庫,沒有則自動創(chuàng)建
IMongoDatabase db = client.GetDatabase("db1");
//拿到集合(表)
IMongoCollection<Student> student = db.GetCollection<Student>("Student");
var data = Builders<Student>.Filter.Where(m => m.age > 21 && m.name.Contains("江"));
var result = student.Find(data).ToList();

分頁查詢：

//與Mongodb建立連接
MongoClient client = new MongoClient("mongodb://127.0.0.1");
//獲得數(shù)據(jù)庫,沒有則自動創(chuàng)建
IMongoDatabase db = client.GetDatabase("db1");
//拿到集合(表)
IMongoCollection<Student> student = db.GetCollection<Student>("Student");
var filter = Builders<Student>.Filter.Where(m => m.age > 21);
FindOptions<Student, Student> findOpt = new FindOptions<Student, Student>();
findOpt.Limit = 2;
findOpt.Skip = 1;
findOpt.Sort = Builders<Student>.Sort.Ascending(m => m.age).Descending(m => m.name);
var result = (student.FindAsync(filter, findOpt).Result).ToList();

數(shù)據(jù)更新：

//與Mongodb建立連接
MongoClient client = new MongoClient("mongodb://127.0.0.1");
//獲得數(shù)據(jù)庫,沒有則自動創(chuàng)建
IMongoDatabase db = client.GetDatabase("db1");
//拿到集合(表)
IMongoCollection<Student> student = db.GetCollection<Student>("Student");
var filter = Builders<Student>.Filter.Where(m => m.age > 21);
var update = Builders<Student>.Update.Set(m => m.name, "皮卡丘");
//update Student set name="皮卡丘" where age>21
student.UpdateMany(filter, update);

數(shù)據(jù)刪除：

//與Mongodb建立連接
MongoClient client = new MongoClient("mongodb://127.0.0.1");
//獲得數(shù)據(jù)庫,沒有則自動創(chuàng)建
IMongoDatabase db = client.GetDatabase("db1");
//拿到集合(表)
IMongoCollection<Student> student = db.GetCollection<Student>("Student");
var filter = Builders<Student>.Filter.Where(m => m.age > 21);
//delete from Student where age>21
//student.DeleteMany(filter);
student.DeleteOne(filter);//只刪除一個