Unique key applying on asp.net MVC 5 model property

Question

I have User(name,password) model and Roles model(id,role).Now what I want is mapping model(id,Uid,Rid) between these two models and here Uid,Rid foreign keys also Uid should be unique. How can acheive this. I have done with foreign key and with mapping table but I stuck at unique key applying on Uid.

Can anyone help me in this? Thanks in advance.

 public class Image
 {
    public int id { get; set; }

    public string Name{ get; set; }

    public String Password { get; set; }
}

//User roles class
public class Role
{
    public int id { get; set; }

    public string Roles { get; set; }
}

//User mapping with roles
public class Rolemapping
{
    public int id { get; set; }

    public int Uid { get; set; }

    [ForeignKey("Uid")]
    public Image User { get; set; }

    public int Rid { get; set; }

    [ForeignKey("Rid")]
    public Role Role { get; set; }
}

If I include [Key] at the top of Uid than it is becoming Primary Key but I want to apply foreign key and unique key on Uid! — madhu, Jul 10 '14 at 08:02
FYI Foreign key constraint is being implemented on a primary key if I'm not wrong — Arijit Mukherjee, Jul 10 '14 at 08:03

score 3 · Accepted Answer · edited May 23 '17 at 12:33

3

Unique Key in Model Code First

Follow the above link to create Unique Key prior to EF 6.1 and

EF 6.1 onwards you can easily have unique constrains ,

[Index("TitleIndex", IsUnique = true)]

public string Title { get; set; }

edited May 23 '17 at 12:33

Community

1
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answered Jul 10 '14 at 08:09

Arijit Mukherjee

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Thanks I am using EF 6.1 and this solution fits my issue :) – madhu Jul 10 '14 at 09:20

score 0 · Answer 2 · answered Feb 24 '23 at 12:53

If you are using MYSQL you are likely to get BLOB/TEXT column 'value' used in key specification without a key length so add a key length

[Index("TitleIndex", IsUnique = true)]
[MaxLength(15)]
public string Title { get; set; }

This will change the field type to varchar as well

Unique key applying on asp.net MVC 5 model property

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