EF Core HasMaxLength

The HasMaxLength method is applied to a property to specify a maximum number of characters or bytes for the column that the property should map to. The following example specifies that the Title column in the Books table is to have a maximum length of 150 characters instead of the default which is unlimited:

public class SampleContext : DbContext
{
    public DbSet<Book> Books { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Book>()
            .Property(b => b.Title).HasMaxLength(150);
    }
}

public class Book
{
    public int BookId { get; set; }
    public string Title { get; set; }
    public Author Author { get; set; }
}

Data Annotations

The Data Annotations equivalents to the HasMaxLength method are the MaxLength attribute and the StringLength attribute.