EF Core 5 byte[] null in database

Question

I´m creating a WebAPI for an already existing database. In one table, the primary key column starts at -1. When I call

            var test = await Contexts.CustomerDbContext.ShipCarriers.ToListAsync();
            var test2 = await  Contexts.CustomerDbContext.ShipCarriers.FirstOrDefaultAsync(x => x.ShipCarrierId == 0);
            var test3 = await  Contexts.CustomerDbContext.ShipCarriers.FirstOrDefaultAsync(x => x.ShipCarrierId == -1);

In

var test =await Contexts.CustomerDbContext.ShipCarriers.ToListAsync();

the first two entries are null and for

var test2 = await Contexts.CustomerDbContext.ShipCarriers.FirstOrDefaultAsync(x => x.ShipCarrierId == 0);

var test3 = await Contexts.CustomerDbContext.ShipCarriers.FirstOrDefaultAsync(x => x.ShipCarrierId == -1);

both are null.

Here are the class and the configuration I´m using

public class ShipCarrierConfiguration : IEntityTypeConfiguration<ShipCarrierDbObject>
{
    public void Configure(EntityTypeBuilder<ShipCarrierDbObject> builder)
    {
        
    }
}   
 

[Table("spedition")]
public class ShipCarrierDbObject 
{

    [Key]
    [Column("speditionid")]
    public int? ShipCarrierId {get ;set ;}

    [Column("cloudid")]
    public string CloudId { get; set; }

    [Column("bezeichnung")]
    public string Name { get; set; }
    
    [Column("logo")]
    public byte[]? Logo { get; set; }
    
    [Column("logoform")]
    public byte[]? LogoForm { get; set; }

    [Column("logobutton")]
    public byte[]? LogoButton { get; set; }
    
}

As far as I found the Entity-Framework, in default, starts PKs at 1 and handles values 0 and -1 as invalid keys. Is there a way to change this behavior?

EDIT: I found what was causing the problem. In the database the fields for

[Column("logoform")]
public byte[] LogoForm { get; set; }

[Column("logobutton")]
public byte[] LogoButton { get; set; }

are null for only these two entries. But I don´t understand why that prevents the entries from being loaded. I´m using a PostgreSQL database and the field type for both is bytea.

EF doesn't assign IDs, it merely defaults to expect (and create if code first) identity columns for PKs that follow the *Id naming convention. PKs should not be null-able types, so that ShipCarrierId should be an `int` rather than `int?`. If you want an auto-incrementing ID you will need to set up the identity/sequence manually. (for SQL Server see: https://stackoverflow.com/questions/5974554/ef-code-first-how-to-set-identity-seed) If you don't want an auto-increment then use `[DatabaseGenerated(DatabaseGeneratedOption.None)]` on the key column. — Steve Py, Feb 09 '22 at 10:11
@StevePy Thanks, after some more testing I found that the error has to be in the rest of the class. When I use this reduced model the problem does not occur. I will post an answer after finding the source of this problem. — Tobias Mikutta, Feb 09 '22 at 11:02

score 0 · Accepted Answer · edited Feb 15 '22 at 08:22

0

As I could not get EF to read the null values from my DB into the byte[] I added a 1x1px transparent image into the database.

edited Feb 15 '22 at 08:22

Dharman

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answered Feb 15 '22 at 07:17

Tobias Mikutta

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Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Feb 15 '22 at 07:25

EF Core 5 byte[] null in database

1 Answers1