C#•3mo 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}OP•3mo 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•3mo ago

your OwnerId should be NULL, not 0

{sus}OP•3mo ago

Can it be zero?

Insire•3mo ago

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

{sus}OP•3mo ago

Hmmmm Let me try

Insire•3mo ago

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

{sus}OP•3mo ago

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

{sus}OP•3mo ago

Insire•3mo 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}OP•3mo ago

I already put null as the default value

{sus}OP•3mo ago

Insire•3mo ago

why do you even set that, just remove the attribute

{sus}OP•3mo ago

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

Insire•3mo ago

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

cathei•3mo ago

Do you have Id column in Owner?

{sus}OP•3mo 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•3mo ago

Paste the code of your Owner class?

{sus}OP•3mo ago

Insire•3mo ago

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

{sus}OP•3mo ago

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

Insire•3mo ago

this is the code lvl

{sus}OP•3mo 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•3mo ago

Oh you are saying you putting 0 as seed

{sus}OP•3mo ago

Yes.

cathei•3mo ago

Why not null?

{sus}OP•3mo ago

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

cathei•3mo ago

As a seed

{sus}OP•3mo ago

instead of null, for sanity purposes

cathei•3mo ago

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

{sus}OP•3mo ago

OHH

cathei•3mo ago

And validation fails

{sus}OP•3mo 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