static void Main(string[] args) { using (MYContext ctx = new MYContext()) { //ctx.Database.Log = F; ctx.Database.Log = (sql) => { Console.WriteLine("*************Log**********" + sql); }; /* * Person p1 = new Person(); * p1.Age = 18; * p1.CreateDateTime = DateTime.Now; * p1.Name = "EF"; * ctx.Persons.Add(p1);*/ /* * Dog d = new Dog(); * d.Name = "旺财"; * //ctx.Dogs.Add(d); * ctx.Set<Dog>().Add(d); * Console.WriteLine("Id="+d.Id); * ctx.SaveChanges(); * Console.WriteLine("Id=" + d.Id);*/ // IQueryable<Person> persons = ctx.Persons.Where(p=>p.Age>10); //var persons = ctx.Persons.Where(p=>p.Age>10); /* * var persons = from p in ctx.Persons * where p.Age > 10 * select p; * foreach(var p in persons) * { * Console.WriteLine(p); * }*/ //var person = ctx.Persons.Where(p => p.Id == 4).SingleOrDefault(); /* * var person = ctx.Persons.SingleOrDefault(p=>p.Id==4); * if(person==null) * { * Console.WriteLine("已被删除"); * } * else * { * ctx.Persons.Remove(person); * ctx.SaveChanges(); * }*/ /* * ctx.Persons.RemoveRange(ctx.Persons.Where(p => p.Age > 10)); * ctx.SaveChanges();*/ /* * var persons = ctx.Persons; * foreach(var p in persons) * { * p.Age++; * } * ctx.SaveChanges();*/ /* * var items = from p in ctx.Persons * group p by p.Age into g1 * select new { Age = g1.Key, Count = g1.Count(), IdMax = g1.Max(p => p.Id) }; * foreach(var item in items) * { * Console.WriteLine(item.Age+"="+item.Count+","+item.IdMax); * }*/ /* * var items = from p in ctx.Persons * orderby p.Age * select p; * foreach(var p in items) * { * Console.WriteLine(p); * }*/ // var items = ctx.Persons.OrderBy(p=>p.Age).Skip(1).Take(2); /* * var items = (from p in ctx.Persons * orderby p.Age * select p).Skip(1).Take(2);//.ToList(); * * Console.WriteLine("准备开始foreach喽!!!!!!!!!"); * foreach (var p in items) * { * Console.WriteLine(p); * }*/ /* * Person p = ctx.Persons.First(); * p.Name = "rrr"; * p.Age = 666; * ctx.SaveChanges();*/ //long[] ids = { 2, 5, 6 };//不要写成int[] // var result = ctx.Persons.Where(p => ids.Contains(p.Id)); //必须写成IQueryable<Person>,如果写成IEnumerable就会在内存中取后续数据 /* * IQueryable<Person> result = ctx.Persons.Where(p=>p.Id>3); * result = result.Where(p=>p.Name.Length>3); * * result.ToList();*/ /* * string name = Console.ReadLine(); * int age = 888; * ctx.Database.ExecuteSqlCommand("insert into T_Persons(Name,CreateDateTime,Age) values({0},GetDate(),{1})", name, age);*/ /* * var result = ctx.Database.SqlQuery<GroupCount>("select age,count(*) AgeCount from T_Persons group by Age"); * foreach(GroupCount item in result) * { * Console.WriteLine(item.Age+"="+item.AgeCount); * }*/ /* * var result = ctx.Database.SqlQuery<Person>("select * from T_Persons"); * foreach(var p in result) * { * Console.WriteLine(p); * }*/ /* * var result = ctx.Database.SqlQuery<string>("select Name from T_Persons"); * foreach(string item in result) * { * Console.WriteLine(item); * }*/ /* * int i = ctx.Database.SqlQuery<int>("select count(*) from T_Persons").Single(); * Console.WriteLine(i);*/ // var result = ctx.Persons.Where(p=>SqlFunctions.DateDiff("hour",p.CreateDateTime,DateTime.Now)>1); //var result = ctx.Persons.Where(p => (DateTime.Now - p.CreateDateTime).TotalHours > 1); //var result = ctx.Persons.Where(p => p.Id==3); //var result = ctx.Persons.Where(p => Convert.ToString(p.Id) == "3"); //result.ToList(); // Person p1 = ctx.Persons.SingleOrDefault(p => p.Id == 1); /* * Person p1 = new Person() {Id=1,Age=666,CreateDateTime=DateTime.Parse("2017-03-14 16:38:25.417"),Name="rrr" }; * ctx.Persons.Remove(p1); * //p1.Age++; * ctx.SaveChanges();*/ /* * Person p1 = new Person() { Age=119, * CreateDateTime =DateTime.Now,Name="hj"}; * Console.WriteLine(ctx.Entry(p1).State); * //ctx.Entry(p1).State = System.Data.Entity.EntityState.Added; * ctx.Persons.Add(p1); * Console.WriteLine(ctx.Entry(p1).State); * * ctx.SaveChanges(); * Console.WriteLine(ctx.Entry(p1).State);*/ /* * Person p1 = new Person { Id=1}; * Console.WriteLine(ctx.Entry(p1).State); * ctx.Persons.Attach(p1); * Console.WriteLine(ctx.Entry(p1).State); * p1.Name = "rupeng.com"; * Console.WriteLine(ctx.Entry(p1).State); * ctx.SaveChanges(); * Console.WriteLine(ctx.Entry(p1).State);*/ /* * Person p1 = ctx.Persons.First(); * Console.WriteLine(ctx.Entry(p1).State); * p1.Age = 111; * Console.WriteLine(ctx.Entry(p1).State); * ctx.SaveChanges(); * Console.WriteLine(ctx.Entry(p1).State); */ /* * Person p1 = ctx.Persons.First(); * Console.WriteLine(ctx.Entry(p1).State); * //ctx.Persons.Remove(p1); * ctx.Entry(p1).State = System.Data.Entity.EntityState.Deleted; * Console.WriteLine(ctx.Entry(p1).State); * ctx.SaveChanges(); * Console.WriteLine(ctx.Entry(p1).State); * * //ctx.Persons.Add(p1); * ctx.Entry(p1).State = System.Data.Entity.EntityState.Added; * ctx.SaveChanges(); * Console.WriteLine(ctx.Entry(p1).State); */ /* * Person p1 = new Person(); * p1.Id = 6; * p1.Name = "如鹏网"; * Console.WriteLine(ctx.Entry(p1).State); * ctx.Persons.Attach(p1); * Console.WriteLine(ctx.Entry(p1).State); * ctx.Entry(p1).Property(e => e.Name).IsModified = true; * Console.WriteLine(ctx.Entry(p1).State); * ctx.SaveChanges(); * Console.WriteLine(ctx.Entry(p1).State);*/ /* * foreach(var p in ctx.Persons.AsNoTracking().Where(p=>p.Id>5)) * { * * p.Age++; * Console.WriteLine(p); * }*/ var p = ctx.Persons.AsNoTracking().First(); Console.WriteLine(ctx.Entry(p).State); ctx.Entry(p).State = System.Data.Entity.EntityState.Unchanged; p.Name = "哈哈哈哈"; Console.WriteLine(ctx.Entry(p).State); ctx.SaveChanges(); Console.ReadKey(); } }
static void Main(string[] args) { using (MYContext ctx = new MYContext()) { /* * Person p1 = new Person(); * p1.Age = 18; * p1.CreateDateTime = DateTime.Now; * p1.Name = "EF"; * ctx.Persons.Add(p1);*/ /* * Dog d = new Dog(); * d.Name = "旺财"; * //ctx.Dogs.Add(d); * ctx.Set<Dog>().Add(d); * Console.WriteLine("Id="+d.Id); * ctx.SaveChanges(); * Console.WriteLine("Id=" + d.Id);*/ // IQueryable<Person> persons = ctx.Persons.Where(p=>p.Age>10); //var persons = ctx.Persons.Where(p=>p.Age>10); /* * var persons = from p in ctx.Persons * where p.Age > 10 * select p; * foreach(var p in persons) * { * Console.WriteLine(p); * }*/ //var person = ctx.Persons.Where(p => p.Id == 4).SingleOrDefault(); /* * var person = ctx.Persons.SingleOrDefault(p=>p.Id==4); * if(person==null) * { * Console.WriteLine("已被删除"); * } * else * { * ctx.Persons.Remove(person); * ctx.SaveChanges(); * }*/ /* * ctx.Persons.RemoveRange(ctx.Persons.Where(p => p.Age > 10)); * ctx.SaveChanges();*/ /* * var persons = ctx.Persons; * foreach(var p in persons) * { * p.Age++; * } * ctx.SaveChanges();*/ /* * var items = from p in ctx.Persons * group p by p.Age into g1 * select new { Age = g1.Key, Count = g1.Count(), IdMax = g1.Max(p => p.Id) }; * foreach(var item in items) * { * Console.WriteLine(item.Age+"="+item.Count+","+item.IdMax); * }*/ /* * var items = from p in ctx.Persons * orderby p.Age * select p; * foreach(var p in items) * { * Console.WriteLine(p); * }*/ // var items = ctx.Persons.OrderBy(p=>p.Age).Skip(1).Take(2); var items = (from p in ctx.Persons orderby p.Age select p).Skip(1).Take(2); foreach (var p in items) { Console.WriteLine(p); } Console.ReadKey(); } }