[英]Entity Framework Creates Unwanted Records In Database in one to many relationships
I am using codefirst technique in my MVC ASP.NET application to generate my database. 我在MVC ASP.NET应用程序中使用Codefirst技术生成数据库。 I attempted to Create a one to many relationship between two of my tables, Customer and Room. 我试图在两个表“客户”和“房间”之间创建一对多关系。
I want one customer to be able to book one or more than one room. 我希望一位客户能够预订一间或多间客房。
The Following is my Customer model: 以下是我的客户模型:
public class Customer
{
public int id { get; set; }
[Display(Name = "Name")]
public string name { get; set; }
[Display(Name = "Email Address")]
public string email { get; set; }
[Display(Name = "Phone Number")]
public string phoneno { get; set; }
[Display(Name = "Date of Birth")]
public DateTime DOB { get; set; }
[Display(Name = "CNIC")]
public string cnic { get; set; }
public List<int> Roomsid { get; set; }
[Display(Name = "Check In Date")]
public DateTime? checkin { get; set; }
[Display(Name = "Check Out Date")]
public DateTime? checkout { get; set; }
public List<Room> Room { get; set; }
}
And the following is model 以下是模型
public class Room
{
public int id { get; set; }
public int floorno { get; set; }
public string roomclass { get; set; }
public int cost { get; set; }
public string bedcount { get; set; }
public string facilities { get; set; }
public string description { get; set; }
public int? Customerid { get; set; }
}
Let's say when ever I pass a Customer object to my database, entity frameworks creates new Room records even when I define the RoomID for the relevant customer entries. 假设当我将客户对象传递到数据库时,即使我为相关客户条目定义了RoomID,实体框架也会创建新的Room记录。
Let me elaborate, let's say I run the following code: 让我详细说明一下,假设我运行以下代码:
ApplicationDbContext x = new ApplicationDbContext();
var a = new Customer() { };
var b = new List<Room>() {
new Room { id=2 ,floorno=2, bedcount="2", cost=2, description="2", facilities="2", roomclass="2" },
new Room {id=3 ,floorno=3, bedcount="3", cost=2, description="3", facilities="3", roomclass="3" },
new Room {id=4 ,floorno=4, bedcount="4", cost=4, description="4", facilities="4", roomclass="4" },
};
a.checkin = Convert.ToDateTime("05 Mar 2017");
a.checkout = Convert.ToDateTime("07 Mar 2017");
a.DOB = Convert.ToDateTime("02 Mar 2000");
a.cnic = "asfsgwlkgnwe98hf0";
a.email = "agjw98e98weg98";
a.name = "Äfnan Makhdoom";
a.Rooms = b;
x.Customers.Add(a);
x.SaveChanges();
Or even when I don't define any other parameter except the room id in my variable b, I get additional records created in my Rooms table in my database. 甚至即使我没有在变量b中定义房间ID以外的任何其他参数,我也会在数据库的“房间”表中创建其他记录。
Even when I choose RoomID as 1, it will create a new record with a new RoomID with other fields the same as I define them. 即使将RoomID选择为1,它也会使用其他与我定义的相同字段的新RoomID创建新记录。 Any help? 有什么帮助吗?
If all you are trying to do is add a Customer to an existing Room, you could do something like this. 如果您要做的就是将客户添加到现有会议室,则可以执行以下操作。
var a = new Customer() { };
var roomWithId3 = x.Rooms.Single(x => x.Id == 3);
a.rooms.Add(roomWithId3);
x.Customers.Add(a);
x.SaveChanges();
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