1.2 EntityFramework簡單增删改查

//添加對象
            Students objStudent = new Students()
            {
                StudentAddress = "天津市南開區",
                StudentName = "CZB",
                Age = 26,
                Birthday = Convert.ToDateTime("1992-02-29"),
                ClassId = 2,
                Gender = "男",
                PhoneNumber = "022-99008877",
                StudentIdNo = 120223199601011213
            };
            EFDBEntities efdb = new EFDBEntities();
            efdb.Students.Add(objStudent);//将實體對象添加到資料庫上下文對應的對象集合中
            int result = efdb.SaveChanges();//将資料庫上下文的更改儲存到資料庫中

            Console.WriteLine(result);
            Console.ReadLine();
           

//删除對象
            EFDBEntities efdb = new EFDBEntities();
            //想修改對象，首先找到要修改的對象
            Students objStudent = efdb.Students.FirstOrDefault(s => s.StudentId == 100012);

            efdb.Students.Remove(objStudent);

            int result = efdb.SaveChanges();
            Console.WriteLine(result);
            Console.ReadLine();
           

//查詢對象
            //建立資料庫上下文對象
            EFDBEntities efdb = new EFDBEntities();
            Students objStudent = efdb.Students.SingleOrDefault(s => s.StudentName ==               "CZB");
            if (objStudent != null)
            {
                Console.WriteLine(objStudent.StudentName + "  " + objStudent.StudentId);
            }

            //使用where()查詢符合條件的資料
            IQueryable<Students> query = efdb.Students.Where(s => s.StudentId > 100002);
            Console.WriteLine("學号\t姓名\t年齡");
            foreach (var item in query)
            {
                Console.WriteLine("{0}\t{1}\t{2}", item.StudentId, item.StudentName, item.Age);
            }
            Console.ReadLine();
           

//修改對象
            EFDBEntities efdb = new EFDBEntities();
            //想修改對象，首先找到要修改的對象
            Students objStudent = efdb.Students.FirstOrDefault(s => s.StudentId == 100012);
            //Students objStudent = (from s in efdb.Students
            //                       where s.StudentId == 100012
            //                       select s).First<Students>();
            //在此修改各個屬性值
            objStudent.StudentAddress = "哈哈哈";
            objStudent.PhoneNumber = "888888888";
            int result = efdb.SaveChanges();
            Console.WriteLine(result);
            Console.ReadLine();