Violation of PRIMARY KEY constraint. Cannot insert duplicate key

I'm using a `List` object to contain items from a secondary table that my primary table has a one-to-many relationship with. The `PK` of the primary table serves as the `FK` field on the secondary table. However, I'm getting this error when the record attempts to save ``` Violation of PRIMARY KEY constraint 'PK_ClearinghousePartners'. Cannot insert duplicate key in object 'dbo.ClearinghousePartners'. The duplicate key value is (0) ``` Primary Table Model FYI - this table contains a LARGE number of fields so I'm just showing the `List` ``` public partial class AgentTransmission { . . public virtual List<ClearinghousePartners> ClearinghousePartners { get; set; } } ``` Secondary Table Model ``` public partial class ClearinghousePartners { public int Id { get; set; } public string ClearingHouseName { get; set; } public string TradingPartnerName { get; set; } public Nullable<System.DateTime> StartDate { get; set; } public int AgtTransId { get; set; } //FK field corresponds to 'Id' on AgentTransmission public virtual AgentTransmission AgentTransmission { get; set; } } ``` Controller When the model posts back to the controller to save the exception is thrown in this area of the code. This is an instance in which the `AgentTransmission` object is completely new and needs to be added to the database. Same goes for each item in the `ClearinhousePartners` collection. Each are brand new `ClearinghousePartners` items with no values for `Id` and `AgtTransId` fields. I need the `AgentTransmission` object to save first so it's `Id` field can be created and THEN inserted into the `AgtTransId` field in the `ClearinghousePartners` objects. ``` agenttransmission.LastChangeDate = DateTime.Now; agenttransmission.LastChangeOperator = Security.GetUserName(User); db.AgentTransmission.Add(agenttransmission); db.SaveChanges(); //Exception thrown here ``` View ``` <fieldset id="ClearinghousePartners"> <legend>Clearinghouse Partners</legend> <center> <table> <thead> <th>Clearinghouse Name</th> <th>Trading Partner Name</th> <th>Start Date</th> </thead> <tbody> @for (int i = 0; i < Model.ClearinghousePartners.Count(); i++) { <tr align="center"> @Html.HiddenFor(model => model.ClearinghousePartners[i].Id) @Html.HiddenFor(model => model.ClearinghousePartners[i].AgtTransId) <td>@Html.TextBoxFor(model => model.ClearinghousePartners[i].ClearingHouseName, new { style = "width: 100px" })</td> <td>@Html.TextBoxFor(model => model.ClearinghousePartners[i].TradingPartnerName, new { style = "width: 100px" })</td> <td>@Html.TextBoxFor(model => model.ClearinghousePartners[i].StartDate, new { style = "width: 100px" })</td> </tr> } </tbody> </table> </center> </fieldset> ```