第一篇文章《EF Core 实践教程（一）配置环境及使用code first 创建数据库 》介绍EF Core通过code first方式创建了数据库，及实现了实体类及相关配置，本文将基于上篇文章的实现完成对数据库的增、删、改、查功能，代码很简单，具体代码如下：

        public async Task<IActionResult> Index()
        {
            TestDbContext dbContext = new TestDbContext();
            //增加
            Book model = new Book();
            model.Title = "测试文章";
            model.Price = 50;
            model.PubTime = DateTime.Now;
            dbContext.Books.Add(model);

            //查询
            var list = dbContext.Books.Where(x => x.Title == "测试文章");

            //修改
            var modelModify = dbContext.Books.Single(x => x.Title == "测试文章");
            modelModify.Title = "测试文章1";

            //删除
            var modelDel= dbContext.Books.Single(x => x.Title == "测试文章1");
            dbContext.Books.Remove(modelDel);

            //保存到数据库
            await dbContext.SaveChangesAsync();


            return View();
        }