Nullable Mode

The NullableMode property on [Facette] controls how nullability is handled on generated DTO properties.

Modes

AllNullable — PATCH operations

AllNullable makes every property nullable, which is ideal for PATCH/partial update DTOs where omitted fields should remain unchanged:

[Facette(typeof(Employee), "SocialSecurityNumber",
    NullableMode = NullableMode.AllNullable)]
public partial record NullableEmployeeDto;

The generated DTO:

public partial record NullableEmployeeDto
{
    public int? Id { get; init; }           // int → int?
    public string? FirstName { get; init; }  // already nullable-ref
    public decimal? Salary { get; init; }    // decimal → decimal?
    public bool? IsActive { get; init; }     // bool → bool?
    // ...
}

Usage in a PATCH endpoint:

var patchDto = new NullableEmployeeDto
{
    FirstName = "Updated",  // only set what changed
    // everything else is null — meaning "don't change"
};

ToSource with AllNullable

When generating ToSource() for AllNullable DTOs, value types use ?? default to handle null:

// Generated ToSource
Id = this.Id ?? default,
Salary = this.Salary ?? default,
IsActive = this.IsActive ?? default

AllRequired

AllRequired strips nullability from all properties. Use this when you want a strict DTO where every field must be provided:

[Facette(typeof(Employee), "SocialSecurityNumber",
    NullableMode = NullableMode.AllRequired)]
public partial record StrictEmployeeDto;

Properties like Address? HomeAddress would become Address HomeAddress (non-nullable).

Auto

The default mode. Each generated property matches the nullability of the corresponding source property exactly.