快速参考

此页面展示了多个命令的提供者语法以及它们相关联的 API 文档链接。

命令

语法

配置 DBContext

API 文档
基础知识

public class PlanetDbContext : DbContext
{
    public DbSet<Planet> Planets { get; init; }
    public static PlanetDbContext Create(IMongoDatabase database) =>
        new(new DbContextOptionsBuilder<PlanetDbContext>()
            .UseMongoDB(database.Client, database.DatabaseNamespace.DatabaseName)
            .Options);
    public PlanetDbContext(DbContextOptions options)
        : base(options)
    {
    }
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        modelBuilder.Entity<Planet>().ToCollection("planets");
    }
}

创建 DBContext 实例

基础知识

// Replace the placeholder with your connection URI
var client = new MongoClient("<Your connection URI>");
var db = PlanetDbContext.Create(client.GetDatabase("sample_planets"));

查找实体

API 文档
基础知识

var planet = db.Planets.FirstOrDefault(p => p.name == "Mercury");
Console.WriteLine(planet.name);

Mercury

查找多个实体

API 文档
基础知识

var planets = db.Planets.Where(p => p.hasRings == true);
foreach (var p in planets)
{
   Console.WriteLine(p.name);
}

Neptune
Uranus
Saturn
Jupiter

插入实体

API 文档
基础知识

db.Planets.Add(new Planet()
{
    name = "Pluto",
    hasRings = false,
    orderFromSun = 9
});
db.SaveChanges();

插入多个实体

API 文档
基础知识

var planets = new[]
{
    new Planet()
    {
        _id = ObjectId.GenerateNewId(),
        name = "Pluto",
        hasRings = false,
        orderFromSun = 9
    },
    new Planet()
    {
        _id = ObjectId.GenerateNewId(),
        name = "Scadrial",
        hasRings = false,
        orderFromSun = 10
    }
};
db.Planets.AddRange(planets);
db.SaveChanges();

更新实体

API 文档
基础知识

var planet = db.Planets.FirstOrDefault(p => p.name == "Mercury");
planet.name = "Mercury the first planet";
db.SaveChanges();

更新多个实体

API 文档
基础知识

var planets = db.Planets.Where(p => p.orderFromSun > 0);
foreach (var p in planets)
{
    p.orderFromSun++;
}
db.SaveChanges();

删除实体

API 文档
基础知识

var planet = db.Planets.FirstOrDefault(p => p.name == "Pluto");
db.Planets.Remove(planet);
db.SaveChanges();

删除多个实体

API 文档
基础知识

var pluto = db.Planets.FirstOrDefault(p => p.name == "Pluto");
var scadrial = db.Planets.FirstOrDefault(p => p.name == "Scadrial");
var planets = new[] { pluto, scadrial };
db.Planets.RemoveRange(planets);
db.SaveChanges();

指定获取实体的顺序

API 文档
基础知识

var planetList = db.Planets.OrderBy(p => p.orderFromSun);
foreach (var p in planetList)
{
    Console.WriteLine(p.name);
}

Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune

指定获取实体的多个排序顺序

API 文档
基础知识

var planetList = db.Planets.OrderBy(o => o.hasRings).ThenBy(o => o.name);
foreach (var p in planetList)
{
    Console.WriteLine("Has rings: " + p.hasRings + ", Name: " + p.name);
}

Has rings: False, Name: Earth
Has rings: False, Name: Mars
Has rings: False, Name: Mercury
Has rings: False, Name: Venus
Has rings: True, Name: Jupiter
Has rings: True, Name: Neptune
Has rings: True, Name: Saturn
Has rings: True, Name: Uranus

指定要获取的实体数量

API 文档

var planetList = db.Planets.Take(3);
foreach (var p in planetList)
{
    Console.WriteLine(p.name);
}

Neptune
Mercury
Mars

指定获取时跳过的实体数量

API 文档

var planetList = db.Planets.OrderBy(p => p.orderFromSun).Skip(5);
foreach (var p in planetList)
{
    Console.WriteLine(p.name);
}

Saturn
Uranus
Neptune

快速入门

基础知识