Tax category on order item is NULL

Why is my TaxCategoryId NULL in my OrderItem Table even tough it calculates with my TAX category of 21%?

https://postimg.cc/HJdXRkdh

Do you mean these fields ?
DiscountAmountInclTax and DiscountAmountExclTax
If so, these are used if a Discount is applied to the order item

No I'm talking about the TaxCategoryId

https://postimg.cc/w10YGN4r

teun.progressive wrote:
order item table does not contain TaxCategoryId out of the box. TaxCategoryId exists at product table . OrderItem table contain ProductId