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快速参考

此页面显示多个命令的提供商语法及其相关 API 文档的链接。

命令
语法

配置 DBContext

API 文档
Fundamentals

public class PlanetDbContext : DbContext
{
public DbSet<Planet> Planets { get; init; } = null!;
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");
modelBuilder.Entity<Planet>().Property<string[]>("mainAtmosphere");
}
}

创建 DBContext 的实例

Fundamentals

var client = new MongoClient("<connection string URI>");
var db = PlanetDbContext.Create(client.GetDatabase("sample_guides"));
var planet = db.Planets.FirstOrDefault(p => p.name == "Mercury");
Console.WriteLine(planet?.name);

查找多个实体

API 文档
Fundamentals

var planets = db.Planets.Where(p => p.hasRings);
foreach (var p in planets)
{
Console.WriteLine(p.name);
}
db.Planets.Add(new Planet()
{
name = "Pluto",
hasRings = false,
orderFromSun = 9
});
db.SaveChanges();

插入多个实体

API 文档
Fundamentals

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();
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
Fundamentals

var planets = db.Planets.Where(p => p.orderFromSun > 0);
foreach (var p in planets)
{
p.orderFromSun++;
}
db.SaveChanges();
var planet = db.Planets.FirstOrDefault(p => p.name == "Pluto");
db.Planets.Remove(planet!);
db.SaveChanges();

删除多个实体

API 文档
Fundamentals

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();

指定检索实体的顺序

API 文档
Fundamentals

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

指定多个排序以检索实体

API 文档
Fundamentals

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);
}

指定要检索的实体数量

API 文档

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

指定检索时要跳过的实体数

API 文档

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