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C#•2y ago

Scaffolding Error - Requires a primary key to be defined

Here's the class it's referring to

    public class ImageUris
    {
        [JsonPropertyName("small")]
        public string Small { get; set; }

        [JsonPropertyName("normal")]
        public string Normal { get; set; }

        [JsonPropertyName("large")]
        public string Large { get; set; }

        [JsonPropertyName("png")]
        public string Png { get; set; }

        [JsonPropertyName("art_crop")]
        public string ArtCrop { get; set; }

        [JsonPropertyName("border_crop")]
        public string BorderCrop { get; set; }
    }

    public class ImageUris
    {
        [JsonPropertyName("small")]
        public string Small { get; set; }

        [JsonPropertyName("normal")]
        public string Normal { get; set; }

        [JsonPropertyName("large")]
        public string Large { get; set; }

        [JsonPropertyName("png")]
        public string Png { get; set; }

        [JsonPropertyName("art_crop")]
        public string ArtCrop { get; set; }

        [JsonPropertyName("border_crop")]
        public string BorderCrop { get; set; }
    }

I'll be honest I've read the key info in the error link and don't exactly understand what all of this means. I don't quite understand how keys work either.

35 Replies

FroH.LVT•2y ago

Maybe you need one of those: 1. Property name ID 2. Add attribute called [Key] to one of your current property 3. Define your Key on ModelCreating 4. Tell EF that your entity doesn't have key using .HasNoKey()

BigggMoustache•2y ago

Yeah I get that much, I guess I should ask what a key does. I don't really understand this despite trying to read on the docs so I have a Card { ImageUris ImageUris { get; set; } and then ImageUris { ... }

mikepattyn•2y ago

A key is the column/property of your row/object by which that object or row will be identified

BigggMoustache•2y ago

okie doke

mikepattyn•2y ago

You can work without tho as says the description you posted

BigggMoustache•2y ago

yeah I'm just not understanding tbh

mikepattyn•2y ago

You know SQL right?

BigggMoustache•2y ago

I mean I vaguely understand, but in practice of what I'm trying to do vaguely, I've done a few tutorials

mikepattyn•2y ago

Okay,

BigggMoustache•2y ago

Can I just ask a couple dumb questions particular to what I'm doing? Or questions I imagine will help me understand? lol

mikepattyn•2y ago

sure sure, ask away

BigggMoustache•2y ago

What Could I use as a primary key for the imagesUris?

FroH.LVT•2y ago

@@

mikepattyn•2y ago

public int Id {get; set;} 🙂

BigggMoustache•2y ago

the json doesn't serve an ID for the images

FroH.LVT•2y ago

u mean you don't want user to see your ID in Json?

BigggMoustache•2y ago

again, I'm sorry lol. I am a brick.

mikepattyn•2y ago

no no he dont wna see id he dno what to do with id

BigggMoustache•2y ago

No no, I just wholly don't understand this concept

mikepattyn•2y ago

where do you get the json?

BigggMoustache•2y ago

from an api, I'm trying to make a magic the card game deck building app figure that'd be a fun practical way to learn working SQL

mikepattyn•2y ago

cool it is but if you dont get the [Key] concept, i wouldnt continue on until i do

BigggMoustache•2y ago

So next question I guess. I can take any property in the ImageUris make it the PK, and the Card object will know to associate that specific set of ImageUris with it? I get the idea, I just don't get how to use it I just have to slap a PK on a property, and it'll keep track of which card references which images?

mikepattyn•2y ago

no not just any property

BigggMoustache•2y ago

lol okay

mikepattyn•2y ago

in sql database, records are indexed. An integer is the best to do this You should add public int to your urls model

BigggMoustache•2y ago

the image urls will be unique so I figured that'd be good lol

mikepattyn•2y ago

and make the Id column in sql to PRIMARY AUTO INCREMENT Well it can work without PK like you say, the urls are unique you just have to configure the entity in the OnModelCreating..

BigggMoustache•2y ago

I'm all ears bud. I'll google PRIMARY AUTO INCREMENT too when we're done Yeah I haven't done annnything like that only automated stuff and some sql functions in pgadmin / SSMS I did see some stuff like that in docs so I'll take a second look. I really didn't think it'd be this difficult lol. Every step of this programming journey has felt like climbing a mountain to find another mountain xD

mikepattyn•2y ago

Thts the job lol But why dont you take a udemy course ?

BigggMoustache•2y ago

Well I've done a few MVC tutorials, one was an entire course So I was hoping I'd be able to get it off the ground, but turns out nope

mikepattyn•2y ago

Sure you will

BigggMoustache•2y ago

Should I take an EFCore specific class

mikepattyn•2y ago

I can screenshare and setup an example real quick if u want

BigggMoustache•2y ago

sure that'd be really cool.

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