先自定义一个查询语句
int[] nums = new int[7] { 1, 2, 3, 4, 5, 6, 7 };
//var onum = from int n in nums where n % 2 == 0 select n;
//foreach (var item in onum)
//{
// Console.WriteLine(item);
//}
//Console.Read();
//查询用户的角色以及名称含有主任的
下面是几钟常见查询方法
RbacDBEntities db = new RbacDBEntities();
//var user = from UserInfo p in db.UserInfos where p.Name.Contains("主任") select p;
//using (db)
//{
// var n = db.UserInfos.Where(p => p.Name.Contains("主任")).Select(p => new { p.Name,roleName=p.Role.Name}).ToList();
// foreach (var item in n)
// {
// Console.WriteLine(item.Name+"\t"+item.roleName);
// }
// Console.Read();
//}
//显示各角色的用户数 显示角色id 用户数量
//var num = from n in db.UserInfos
// group n by n.RoleID into g
// select new { roleID=g.Key, nums = g.Count() };
// foreach (var item in num)
// {
// Console.WriteLine(item.roleID +"\t"+item.nums);
// }
//用户数
//var man = db.UserInfos.Count();
// Console.WriteLine(man);
几个基本函数
////roleID最小值
//var min = db.UserInfos.Min(p => p.RoleID);
//Console.WriteLine("最小值:"+min);
//var max = db.UserInfos.Max(p => p.RoleID);
//Console.WriteLine("最大值:" + max);
//var sum = db.UserInfos.Sum(p => p.RoleID);
//Console.WriteLine("和:" + sum);
//var avg = db.UserInfos.Average(p => p.RoleID);
//Console.WriteLine("平均值:" + avg);
//Console.Read();
新增,修改,删除的方法
//string sql = @"insert into roles values('院长','局级干部')";
//int res = db.Database.ExecuteSqlCommand(sql);
//if (res > 0)
//{
// Console.WriteLine("新增成功");
//}
//string sql = @"update roles set Remark=@remark where id=@id6 ";
//SqlParameter[] pare = {
// new SqlParameter("@remark","厅级干部"),
// new SqlParameter("@id6","6")
//};
//int result = db.Database.ExecuteSqlCommand(sql, pare);
//if (result > 0)
//{
// Console.WriteLine("更新成功");
//}
//string sql = "delete from roles where id=7";
//int result = db.Database.ExecuteSqlCommand(sql);
//if (result > 0)
//{
// Console.WriteLine("删除成功");
//}
//获取数据insertRoles
db.insertRoles("方法4", "备注4");
//Role role = new Role()
//{
// Name = "方法1",
// Remark = "备注1"
//};
//db.Entry(role).State = System.Data.Entity.EntityState.Unchanged;
//db.SaveChanges();
//var role = db.Roles.Find(1);
//role.Name = "方法1";
//role.Remark = "备注2";
//db.SaveChanges();
//string sql = @"update roles set Remark=@remark where id=@id6 ";
//SqlParameter[] pare = {
// new SqlParameter("@remark","方法3"),
// new SqlParameter("@id6","6")
//};
//int result = db.Database.ExecuteSqlCommand(sql, pare);
//if (result > 0)
//{
// Console.WriteLine("更新成功");
//}
//db.updateRoles(1,"方法4", "备注4");
//删除方法1
//var role = db.Roles.Find(1);
//db.Entry(role).State = System.Data.Entity.EntityState.Deleted;
//db.SaveChanges();
//删除方法2
//var role = db.Roles.Find(1);
//db.Roles.Remove(role);
//db.SaveChanges();
//删除方法3
db.deleteRoles(1, "方法3", "备注3");
Console.Read();
```