add a new field to a table in v1.9?

is there a tutorial for how to add a field to table for V1.9? I searched, all I can find is for v1.8.

V1.9 seems so different from v1.8, can not find some files.

it seems this question was asked again and again, but really no answer for v1.9 yet.

does it mean we can not add a field to a table, or, too complex?


thanks

what I had done is

1) add the field "PdfFileName" to table OrderProductVariant to the database,
2) update the model;
3) add the property to the OrderProductVariant.cs

what else I should do?

when run the site, it shows this error:

{"Schema specified is not valid. Errors: \r\nThe relationship 'NopSolutions.NopCommerce.BusinessLogic.Data.FK_Nop_OrderProductVariant_Nop_ProductVariant' was not loaded because the type 'NopSolutions.NopCommerce.BusinessLogic.Data.OrderProductVariant' is not available.\r\nThe following information may be useful in resolving the previous error:\r\n

The required property 'PdfFileName' does not exist on the type 'NopSolutions.NopCommerce.BusinessLogic.Orders.OrderProductVariant'.\r\n\r\n\r\nThe relationship 'NopSolutions.NopCommerce.BusinessLogic.Data.FK_Nop_OrderProductVariant_Nop_Order' was not loaded because the type 'NopSolutions.NopCommerce.BusinessLogic.Data.OrderProductVariant' is not available.

.....


I'm lost from here.

thanks