How to replace part of column name with dynamic value

Question

I have the following construction in an update transaction:
$upd_blg_user_usr->addColumn("report_1_user", "NUMERIC_TYPE", "VALUE", "{rsCatReport.id_report}");
The dynamic value, {rsCatReport.id_report}, gets a url variable.
I want this variable to replace the "1" in the column name "report_1_user". Something like this:
$upd_blg_user_usr->addColumn("report_{rsCatReport.id_report}_user", "NUMERIC_TYPE", "VALUE", "{rsCatReport.id_report}");
That construction, however, does not work. Prevents the page from loading. I've tried different constructions but have not hit one one that works.
First, I'm not sure anything will work and second, if some different construction will work, I don't know what it is.
Can anyone answer these questions. Thanks in advance for your help.

Answer 1

What? Are you some kind of genius?
Yes that works perfectly. Thanks as always!
Here's the rationale. The same basic form appears on many different pages. The only difference among the forms is the outcome of submitting the form. The form on different pages takes you to a different download page and a database column is marked to signify that the user downloaded that form. For instance:
report_1_usr
report_2_usr
report_3_usr
And so forth...
Up to now each form has had to include the url variable so the submit would take the user to the right download page and it has had to include a unique reference to the correct database column.
Now I can echo or insert that url variable all over the place, including the reference to the column name in the transaction, so I can use a single instance of the form and include it on all pages.
Thanks for helping me figure out the last step.