<PackageReference Include="System.Data.SqlClient" Version="4.7.0" />

SqlUserDefinedTypeAttribute

public sealed class SqlUserDefinedTypeAttribute : Attribute
Used to mark a type definition in an assembly as a user-defined type (UDT) in SQL Server. The properties on the attribute reflect the physical characteristics used when the type is registered with SQL Server. This class cannot be inherited.
public Format Format { get; }

The serialization format as a Format.

public bool IsByteOrdered { get; set; }

Indicates whether the user-defined type is byte ordered.

public bool IsFixedLength { get; set; }

Indicates whether all instances of this user-defined type are the same length.

public int MaxByteSize { get; set; }

The maximum size of the instance, in bytes.

public string Name { get; set; }

The SQL Server name of the user-defined type.

public string ValidationMethodName { get; set; }

The name of the method used to validate instances of the user-defined type.

A required attribute on a user-defined type (UDT), used to confirm that the given type is a UDT and to indicate the storage format of the UDT.