ClickHouseType

This attribute sets the ClickHouseDbParameter.ClickHouseType property value via a class property, forcing an explicit ClickHouse type name for the generated parameter.

Attribute

Example usage:

public class Person
{
    public ulong Id { get; set; }

    [ClickHouseType("Nullable(DateTime64(3))")]
    public DateTime? CreatedDateUtc { get; set; }
}

Fluent Mapping

To configure via FluentMapper:

FluentMapper
    .Entity<Person>()
    .PropertyValueAttributes(e => e.CreatedDateUtc, new ClickHouseTypeAttribute("Nullable(DateTime64(3))"));

Retrieval

Retrieve the attribute via PropertyValueAttributeCache:

var attribute = PropertyValueAttributeCache
    .Get<Person>(e => e.CreatedDateUtc)?
    .FirstOrDefault(e => e.GetType() == typeof(ClickHouseTypeAttribute));

Or via PropertyValueAttributeMapper:

var attribute = PropertyValueAttributeMapper
    .Get<Person>(e => e.CreatedDateUtc)?
    .FirstOrDefault(e => e.GetType() == typeof(ClickHouseTypeAttribute));

We strongly suggest to always use the PropertyValueAttributeCache to maximize the performance.

The underlying driver infers a plain DateTime CLR parameter as whole-second precision. Writing sub-second values into a DateTime64(N) column silently truncates them unless the parameter’s ClickHouse type is stated explicitly, as in the example above.