RowVersion implementation on Entity Framework for PostgreSQL

Question

I am using Entity Framework 6 with PostgreSQL. I have an entity in which I want to prevent concurrency issues, following this documentation I added a RowVersion property with [Timestamp] attribute, however after saving changes to the entity the column RowVersion value stays the same in the database.

    [Timestamp]
    public byte[] RowVersion { get; set; }

Am I missing something or is there another way to handle it in PostgreSQL?

Answer 1

Just an updated answer for EF Core in case anyone else wanders here.

The Npgsql framework has built-in support for this using the hidden system column xmin that the OP is using in his entity as a NotMapped property.

As referenced here, you can set the xmin column as a concurrency token within EF by calling the UseXminAsConcurrencyToken method on your entity within its OnModelCreating method via Fluent API (a Data Annotation is not available at this time as far as I'm aware).

For anyone already using Fluent API configurations, it's as simple as this:

public class AwesomeEntityConfiguration : IEntityTypeConfiguration<AwesomeEntity>
{
    public void Configure(EntityTypeBuilder<AwesomeEntity> builder)
    {
        builder.UseXminAsConcurrencyToken();
    }
}

Answer 2

/// <summary>
/// Meant to validate concurrency en database update
/// This column is updates itself in database and only works in postgresql
/// </summary>
[ConcurrencyCheck]
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
//[NotMapped]
public string xmin { get; set; }

Had to add [NotMapped] attribute just for the column not to be added in the migration, commented it after database-update.