static void DeleteStudents() { //根据主键构建一个对象 Students student = new Students { StudentId = 100000 }; //第一种写法:通过设置状态 using (StudentManageDBEntities db = new StudentManageDBEntities()) { db.Set <Students>().Attach(student); db.Entry(student).State = EntityState.Deleted; db.SaveChanges(); } //第二种写法:通过remove方法 using (StudentManageDBEntities db = new StudentManageDBEntities()) { db.Set <Students>().Attach(student); db.Students.Remove(student); db.SaveChanges();//跟新到数据库(自动生成SQL语句) } //第三种写法:先查寻,再删除 using (StudentManageDBEntities db = new StudentManageDBEntities()) { var stu = db.Students.Where(o => o.StudentId == 100000).FirstOrDefault(); db.Students.Remove(stu); db.SaveChanges();//跟新到数据库(自动生成SQL语句) } }
static void Delete2() { StudentManageDBEntities db = new StudentManageDBEntities(); Students student = new Students { StudentId = 100013, }; db.Set <Students>().Attach(student); db.Entry(student).State = EntityState.Deleted; //提交 int result = db.SaveChanges();//跟新到数据库(自动生成SQL语句) Console.WriteLine("影响行数:" + result); }