Error: Postgresexception 428C9 cannot insert a non default value into column id

[FatmaSedaOZYURT]

Hi,
I develope my project on VisualStudio with c# and postgresql by using EF codefirst.
When data is created on table, sometimes I got this error: Postgresexception 428C9 cannot insert a non default value into column id.

My class is :
public class MyClass { public long Id; public string Name { get; set; } public string LastName { get; set; } }

And my builder is :
model.Entity<MyClass>().Property(b => b.Id).UseIdentityAlwaysColumn();

And later I done migration section. My table is created.

Without seting an Id, that is, with the default value, I filled other values.
Like this:
{ "Name" : "test", "LastName" : "test1" }
But I have 428C9 error.
What can I do this problem?

[FatmaSedaOZYURT]

Hi,
I tried this model.
model.Entity().Property(b => b.Id).ValueGeneratedOnAdd();

However, I keep getting error 428C9.
For a while, it worked but later I start to take error

[roji]

@FatmaSedaOZYURT can you please submit a minimal, runnable code sample that shows the problem?

[FatmaSedaOZYURT]

Hi @roji,
That is my code:

public class MyClass 
{ 
	public long Id; 
	public string Name { get; set; } 
	public string LastName { get; set; }
}

public async Task<MyClassDto> Create(MyClassDto entityDto)
{
    var entity = _mapper.Map<MyClass>(entityDto);
    entity.DateCreated = DateTime.UtcNow;
    
    await DbContext.Set<MyClass>().AddAsync(entity);
    await DbContext.SaveChangesAsync();
    
    return _mapper.Map<MyClassDto>(entity);
}

[roji]

@FatmaSedaOZYURT that's not a minimal, runnable code sample - it's a fragment that's missing important information such as your model configuration. Please try to put together a minimal console program that triggers the error, and post that here.

[FatmaSedaOZYURT]

Hi, thank you for your interest @roji .
I soluted this problem.
When I look in DB log file, I realized to take error because of different another table. As a result of an incorrect create operation on a different table, most likely the DB locked for this context.

I wonder when the locked context will be opened. 👀