I need a way to assign multiple cells in each row their primary key ID that correlates with the primary key in the table after I pivot the data (which I am doing after I pull the records from the database - I'm creating the datatable manually).

For example, there is an orderID = 100 in the parent table, with these records in the child table:

In the database, there is one record per size/quantity:

ORDERID | Primary Key | Size | quantity

100 | SizeID1 | 9 | 12

100 | SizeID2 | 11 | 1

100 | SizeID3 | 15 | 8

I will create a datatable so that the records will look like this for the child rows in the grid:

ORDERID | Size 9 | Size 11 | Size 15

100 | 12 | 1 | 8

So when the user changes the value for Size 9 (in this case 12 units), I need to know that the cell that holds that quantity is 'SizeID1', and the cell that holds the '1' unit for size 11 is 'SizeID2', and so on.

How do I do that?