带有ASP.Net后端的Azure移动应用程序使用外键将数据发布到SQL Server表

Question

I have an ASP.NET backend for an Azure mobile app. It has two tables one with a foreign key in the dataobjects folder.

public class Claim : EntityData
{
    public string CarReg { get; set; }
    public int StartMileage { get; set; }
    public int? EndMileage { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime? EndDate { get; set; }
    public DateTime? SubmittedDate { get; set; }
    public string UserId { get; set; }
    public virtual ICollection<Petrol> Petrols { get; set; }
}

public class Petrol : EntityData
{
    public int Mileage { get; set; }
    public DateTime PurchaseDate { get; set; }
    public float Quantity { get; set; }
    public Decimal Cost { get; set; }
    public string Station { get; set; }
    public virtual Claim Claim { get; set; }
}

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Conventions.Add(
        new AttributeToColumnAnnotationConvention
 <TableColumnAttribute, string>("ServiceTableColumn", (property, attributes) =>
    attributes.Single().ColumnType.ToString()));
}
public System.Data.Entity.DbSet<Claim> Claims { get; set; }
public System.Data.Entity.DbSet<Petrol> Petrols { get; set; }

The Petrols tables has created a column called Claim_id and I am able to add data to the Petrols table manually (using the id key for one of the existing claim rows).

But when I tried using JSON post calls (using postman), I am only able to post to the Claim table.

I cannot post to the Petrol table using a currently existing Claim id. Below is the syntax I am using.

{
    "station": "testpetrol",
    "cost": 100,
    "quantity": 99,
    "date": "2017-07-26T00:00:00Z",
    "mileage": 100,
    "claim": {
        "deleted": false,
        "updatedAt": "2017-07-26T11:18:54.062Z",
        "createdAt": "2017-07-26T11:18:54.062Z",
        "version": "AAAAAAAAD8U=",
        "id": "6FFFC2B6-C410-4D5A-987B-DA0662F75F03",
        "user_id": "sid:xxxxxxxxxxxxxxxxxxxxx""submitted_date": null,
        "end_date": null,
        start_date": "2017-07-25T00: 00: 00Z",
            "end_mileage": null,
            "start_mileage": 15001,
                 "car_reg": "TestClaim"
                 }
    }
}

Above will post to both the Petrols table and the Claims table if they Claim Id is not already in use, but if the Claim already exists (it gives me a violation of primary key contract error on the Claims table ). What I want to do is post the Petrols table that is related to a Claim table by the foreign key Claim_Id field in the Petrols table. I come from an Asp.net webforms/ SQL background where adding new data with a foreign key is easy. This is my first real go of using Entity framework and I cannot see where I am going wrong. Have I created my objects correctly and related them correctly, or am I using Postman incorrectly?

Answer 1

Above will post to both the Petrols table and the Claims table if they Claim Id is not already in use, but if the Claim already exists (it gives me a violation of primary key contract error on the Claims table ).

AFAIK, if you specific the claim property within the Petrol object and send request against Petrol table, then it would add the new claim record and add the new Petrol record. If the value of claim.id has existed in Claim table, then you would retrieve the error as follows:

If you want to add a new record to Petrol table with a existing Claim_id , you could modify the Petrol model and define the foreign key property as follows:

public class Petrol : EntityData
{
    public int Mileage { get; set; }
    public DateTime PurchaseDate { get; set; }
    public float Quantity { get; set; }
    public Decimal Cost { get; set; }
    public string Station { get; set; }

    public string Claim_Id { get; set; }
    [ForeignKey("Claim_Id")]
    public virtual Claim Claim { get; set; }
}