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C#•3mo ago

✅ Seed cannot be added because of required property ID

The seed entity for entity type 'Series' cannot be added because no value was provided for the required property 'Id'.

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74 Replies

restingphantom•3mo ago

trying to fill in the id like this ↓ , gives me the error : The seed entity for entity type 'Series' cannot be added because another seed entity with the same key value for {'Id'} has already been added.

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Pobiega•3mo ago

you can't do it like that. each time the migration runs, it will have a different ID and conflict with HasData, your IDs must be static the alternative is to run your own seeding function as part of your app, instead of as part of the migrations. that has its own downsides thou

restingphantom•3mo ago

cant I just not povide a ID as my database will just make those?

Pobiega•3mo ago

no, because these wont be provided by the DB these will be part of your migrations

restingphantom•3mo ago

ah

Pobiega•3mo ago

how would EF be able to detect a change to them if their IDs are unknown/can change?

restingphantom•3mo ago

oké so, if I would like to add my series to the database on database creation, how do I need to do that?

Pobiega•3mo ago

"on database creation"? that would be via the migration then and that means you need to have hardcoded IDs or do it as part of a manually written migration step, but that means EF wont know about it and you wont get any help with update statements to it

restingphantom•3mo ago

hmmm For my DB I need this set of series so that I can later link them to my investments (like an Enum), what would be best, setting al the GUIDs manually at database creation or setting all the series after database creation using some sort of Init query or something

Pobiega•3mo ago

we use a pre-startup service at work for stuff like this that syncs up entities from the codebase to the database

restingphantom•3mo ago

so kind of like a query you run after creating the database?

Pobiega•3mo ago

sort of, in a way but fully automated and keeps the entites in sync, so it detects if a new one is added or changed

restingphantom•3mo ago

Cool Ill leave this for now I think, do you maybe also know something about how to set up a DateUpdated column and where to implement the date setting (database or API)

Pobiega•3mo ago

some database support automatic updating of a timestamp whenever the record is modified I prefer doing it in code thou, since I might have several different things to track CreatedAt/By, ModifiedAt/By, etc

restingphantom•3mo ago

I was thinking of letting the DB handle it as its already a temporal table and the DateUpdated will mainly be used by powerBI

leowest•3mo ago

wouldn't that only work for dbfirst thou?

restingphantom•3mo ago

and probably not all data will go through my api thats what I also had struggles with as im doing code first now😅

leowest•3mo ago

because on code first u only have hasdefaultvalue that doesn't do updates but when u create directly in the db u do have attributes u can add to the table creation that will make it auto update a column with say current utc time etc and those are performed by the db

restingphantom•3mo ago

it would be nicer to not have to do that though as I rather have everything being created by code

leowest•3mo ago

ah actually there is something mm ValueGeneratedOnAddOrUpdate() which apparently you can override

restingphantom•3mo ago

do you have a link to the documentation?

leowest•3mo ago

https://learn.microsoft.com/en-us/ef/core/modeling/generated-properties?tabs=fluent-api#datetime-value-generation

Generated Values - EF Core

How to configure value generation for properties when using Entity Framework Core

leowest•3mo ago

so for datetime u need to create a trigger its a bit more complext then just doing it via code imo but its a one time setup

restingphantom•3mo ago

I think that this is better because now the value can be changed without the API and not breaking anything in the process and I can just run a migration on a different server to create the database automaticly

leowest•3mo ago

ngl im reading it and im a bit lost myself on how its implemented haha, I would have to give it a go and see. its dependent on the engine u use sql server for example have something called isrowvesion

restingphantom•3mo ago

unless i have messed something up, it also doesnt work

restingphantom•3mo ago

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restingphantom•3mo ago

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restingphantom•3mo ago

at least, when I eddit something in my database using mssms it doesnt update the UpdatedAt field the temporal table works which is nice

leowest•3mo ago

I will give it a go here and see but im using postgresql

restingphantom•3mo ago

hopefully wont make much of a difference

leowest•3mo ago

well u would be able to see it in the migrations or so I think

restingphantom•3mo ago

I will try dropping my db and remaking it, maybe that does something different

restingphantom•3mo ago

cool

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restingphantom•3mo ago

that doesnt work then and for some reason it also needs me to povide an ID

leowest•3mo ago

DateTime? because it can be empty at first

restingphantom•3mo ago

ofc Updated at still stays null though

leowest•3mo ago

looks like it works

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leowest•3mo ago

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leowest•3mo ago

this is the generated migration

restingphantom•3mo ago

how does your code look inside your DB context

leowest•3mo ago

for a start I just tried this

public class BlogConfiguration : IEntityTypeConfiguration<Blog>
{
    public void Configure(EntityTypeBuilder<Blog> builder)
    {
        builder.Property(x => x.CreatedAt)
            .HasDefaultValueSql("current_timestamp");

        builder.Property(x => x.UpdatedAt)
            .HasDefaultValueSql("current_timestamp")
            .ValueGeneratedOnAddOrUpdate();
            //.Metadata.SetAfterSaveBehavior(Microsoft.EntityFrameworkCore.Metadata.PropertySaveBehavior.Save);
    }
}

public class BlogConfiguration : IEntityTypeConfiguration<Blog>
{
    public void Configure(EntityTypeBuilder<Blog> builder)
    {
        builder.Property(x => x.CreatedAt)
            .HasDefaultValueSql("current_timestamp");

        builder.Property(x => x.UpdatedAt)
            .HasDefaultValueSql("current_timestamp")
            .ValueGeneratedOnAddOrUpdate();
            //.Metadata.SetAfterSaveBehavior(Microsoft.EntityFrameworkCore.Metadata.PropertySaveBehavior.Save);
    }
}

For SQL Server thou u would use getutcdate() apparently, for postgresql current_timestamp

restingphantom•3mo ago

They both still dont work

 protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        // Configure a many-to-many relationship between Ventures and Sdgs.
        modelBuilder.Entity<Venture>()
            .HasMany(e => e.Sdgs)
            .WithMany(e => e.Ventures);

        modelBuilder.Entity<Venture>().Property(x => x.CreatedAt)
            .HasDefaultValueSql("getutcdate()");

        modelBuilder.Entity<Venture>().Property(x => x.UpdatedAt)
            .HasDefaultValueSql("getutcdate()")
            .ValueGeneratedOnAddOrUpdate();

        // Configure the Venture entity to use a temporal table, enabling tracking of data changes over time.
        modelBuilder.Entity<Venture>().ToTable("Venture", e => e.IsTemporal());
    }

 protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        // Configure a many-to-many relationship between Ventures and Sdgs.
        modelBuilder.Entity<Venture>()
            .HasMany(e => e.Sdgs)
            .WithMany(e => e.Ventures);

        modelBuilder.Entity<Venture>().Property(x => x.CreatedAt)
            .HasDefaultValueSql("getutcdate()");

        modelBuilder.Entity<Venture>().Property(x => x.UpdatedAt)
            .HasDefaultValueSql("getutcdate()")
            .ValueGeneratedOnAddOrUpdate();

        // Configure the Venture entity to use a temporal table, enabling tracking of data changes over time.
        modelBuilder.Entity<Venture>().ToTable("Venture", e => e.IsTemporal());
    }

restingphantom•3mo ago

https://learn.microsoft.com/en-us/ef/core/modeling/generated-properties?tabs=data-annotations aha

Generated Values - EF Core

How to configure value generation for properties when using Entity Framework Core

restingphantom•3mo ago

dammit sql getutcdate() needed to be getdate()

leowest•3mo ago

now I wonder if there is one that is just OnUpdate otherwise there isnt much meaning to make DateTime nullable

restingphantom•3mo ago

There is

linqisnice•3mo ago

You already get this info with ValidFrom

restingphantom•3mo ago

Now to fix my GUIDs not working because of some stupid reason True, but unfortionately non technical people aslo need to understand my code 😑

leowest•3mo ago

ah there is perfect

linqisnice•3mo ago

Alright, but you don't need a separate UpdatedAt property you're already versioning with temporal tables which has ValidFrom and ValidTo, which detail when updates occured

restingphantom•3mo ago

depends if there is a way to change the time from the gatdate() to amsterdam then I need it

linqisnice•3mo ago

Yes, it's possible The datetime generated when you configure ValidFrom is utc you can convert from utc to whatever

linqisnice•3mo ago

3

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linqisnice•3mo ago

I use nodatime so conversion is pretty straight forward

restingphantom•3mo ago

are you converting in api or in the database

linqisnice•3mo ago

why would you convert in the database?

leowest•3mo ago

database should always be utc

restingphantom•3mo ago

because my internship location uses powerbi which connects directly to the db thats why i want to do as much as possible there to make it easier for them

linqisnice•3mo ago

but surely hes fetching from the database? u can convert upon fetching

restingphantom•3mo ago

thats why I would like the updated at instead of the validFrom ValidTo even though it does the same thing thats also an option

linqisnice•3mo ago

or do you mean hes looking directly in the database?

restingphantom•3mo ago

it uses a direct query cool, updatedAt is in CET now nvmnd generateValueOnUpdate() doesnt work

leowest•3mo ago

yeah u need to use a trigger

restingphantom•3mo ago

I saw can I make the trigger in Ef Core?

leowest•3mo ago

u can add it to your migration yes but it would be a manual addition

restingphantom•3mo ago

dammit then They will just have to use the temporal thing I guess thanks for the help everyone

leowest•3mo ago

as an example of what mine would look like

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leowest•3mo ago

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leowest•3mo ago

at this point I dont think the ValueGeneratedOnUpdate is even needed thou as the trigger will act on its own according.

leowest•3mo ago

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restingphantom•3mo ago

Thnx, I'll look into it again on monday probably First going to enjoy my weekend😁

leowest•3mo ago

yeah im not sure why u gave up on that, its manual yes, but u have to do it once to the migration. anyway hf

restingphantom•3mo ago

Didnt really give up on it per se. I'll probably get back to it on monday when I'm back in the mood to work on it as some other thing didnt work as well

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