C#•2w ago

Setting a Default Value for Migrations

I have a relationship between two models but the relationship is not required, i.e. the first model which "belongs to" the other model can exists on its own.

class Item {

  [DefaultValue(0)]
  public int? OwnerId {get;set;}
  
  public Owner Owner { get;set; }
}

class Owner {
  ...
}

class Item {

  [DefaultValue(0)]
  public int? OwnerId {get;set;}
  
  public Owner Owner { get;set; }
}

class Owner {
  ...
}

So in essence, class Item can stand on its own but it can also belong to someone. I am getting this when trying to run the database update command for the seed data which has set the OwnerId to 0

The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Items_Owners_OwnerId". The conflict occurred in database "<DB>", table "dbo.Owners", column 'Id'.

32 Replies

{sus}•2w ago

The reason I am doing this is there are "global" Items that can be utilized by anyone, but some items belong to specific people. These items are only accessible to them but not others.

Insire•2w ago

your OwnerId should be NULL, not 0

{sus}•2w ago

Can it be zero?

Insire•2w ago

not with a int? OwnerId the default value for that is NULL

{sus}•2w ago

Hmmmm Let me try

Insire•2w ago

which is what is used for relation ships by your database provider

{sus}•2w ago

No go I still get the error and the migration still puts 0 as a default value

{sus}•2w ago

Insire•2w ago

well, thats what you specified via attribute 0 in a nullable column thats a foreignkey means, that there needs to be an entry on the other side of that relationship which has the primary key value of 0

{sus}•2w ago

I already put null as the default value

{sus}•2w ago

Insire•2w ago

why do you even set that, just remove the attribute

{sus}•2w ago

i just updated the value from 0 to null but lemme try removing it Same problem Hmmmm

Insire•2w ago

then idk. probably something else is wrong aswell this should work

cathei•2w ago

Do you have Id column in Owner?

{sus}•2w ago

Yes. 100% positive I also checked the migrations generated If it helps, the seed data with 0 OwnerId is my only problem All the other seed data that has an ownerId of > 0 is fine

cathei•2w ago

Paste the code of your Owner class?

{sus}•2w ago

Insire•2w ago

if just your seed data is wrong, then correct your seed data and set the ownerid to NULL in there

{sus}•2w ago

That's actually my last result but I want to solve this on code level first if possible

Insire•2w ago

this is the code lvl

{sus}•2w ago

If and when someone decides to regenerate the migrations from scratch, this problem won't exist (if I solve it) Migrations are generated from the model code on a code first approach So yeah

cathei•2w ago

Oh you are saying you putting 0 as seed

{sus}•2w ago

Yes.

cathei•2w ago

Why not null?

{sus}•2w ago

That's also an option, but I'd rather have a place holder value for "global" items

cathei•2w ago

As a seed

{sus}•2w ago

instead of null, for sanity purposes

cathei•2w ago

0 is valid ID So it will try to find a Owner with ID 0

{sus}•2w ago

OHH

cathei•2w ago

And validation fails

{sus}•2w ago

THAT MAKES PERFECT SENSE HOLD ON

The exception 'The seed entity for entity type 'Owner' cannot be added because a non-zero value is required for property 'Id'. Consider providing a negative value to avoid collisions with non-seed data.

The exception 'The seed entity for entity type 'Owner' cannot be added because a non-zero value is required for property 'Id'. Consider providing a negative value to avoid collisions with non-seed data.

lol Quirky let me try a different approach

Gaming

Programming

Setting a Default Value for Migrations