efcore微软官方文档

keys
https://docs.microsoft.com/en-us/ef/core/modeling/keys
按照约定，名为id或<类型名称> Id的属性将被配置为实体的键。


class Car
{
    public string Id { get; set; }
    public string Make { get; set; }
    public string Model { get; set; }
}


class Car
{
    public string CarId { get; set; }
    public string Make { get; set; }
    public string Model { get; set; }
}


可以使用数据注释将单个属性配置为实体的键
class Car
{
    [Key]
    public string LicensePlate { get; set; }
    public string Make { get; set; }
    public string Model { get; set; }
}


https://docs.microsoft.com/en-us/ef/core/querying/basic
加载所有数据
using (var context = new BloggingContext())
{
    var blogs = context.Blogs.ToList();
}


using (var context = new BloggingContext())
{
    var blog = context.Blogs
        .Single(b => b.BlogId == 1);
}


删除
using (var context = new BloggingContext())
{
    var blog = context.Blogs.First();
    context.Blogs.Remove(blog);
    context.SaveChanges();
}

更新
using (var context = new BloggingContext())
{
    var blog = context.Blogs.First();
    blog.Url = "http://sample.com/blog";
    context.SaveChanges();
}

添加
using (var context = new BloggingContext())
{
    var blog = new Blog { Url = "http://sample.com" };
    context.Blogs.Add(blog);
    context.SaveChanges();
    Console.WriteLine(blog.BlogId + ": " +  blog.Url);
}