Applescript - how do I use the result of a library return value

Question

Hello.  Been using applescript for about a week.  Very new.
I'm using the following script below using an external libarary to query mysql database on external server.  works.  gives results.  How do I save them to do something with the. 
when I run it, the results of the call to the library show up in the results window.  that makes sense.
ie
{rows:1, cols:1, record_data:{{"85016   "}}}
I want to assign the results to a variable to use it later, particularly the 85016.
I try "set testVariable to tell db_link to do_select(theDBCommand)"
no good.  Not sure how to do this.
Help appreciated.
Script follows:
-- links to the mysql tools - thanks to http://www.j-schell.de/node/80
set library_path to "js_aux_scripts:mysql_objects.scptd"
set app_support to (path to application support folder) as string
set DB_Library to (load script file (app_support & library_path))
set db_link to new_link("lala.yadayada.com", "user", "pass", "db") of DB_Library
-- collect the job number you want to run
-- Get the Number
set displayString to "Enter Job Number"
set the theIcon to 1
set theJobNumber to ""
repeat
  display dialog displayString default answer theJobNumber with icon theIcon
          set theJobNumber to text returned of result
          try
                    if theJobNumber = "" then error
                    set theJobNumber to theJobNumber as number
                    exit repeat
          on error
                    set displayString to "INVALID ENTRY! " & displayString
                    set theIcon to 0
          end try
end repeat
-- Query the database and get the other informtion from the ticket file.
set theDBCommand to "SELECT BaseId from SfComp where JobNo = " & theJobNumber
tell db_link to do_select(theDBCommand)

Answer 1

Usually you would assign the variable to the results of the command/function, which are inside the tell statement -for example:
tell db_link to set testVariable to do_select(theDBCommand)
The results are a record, where it looks like record_data is a list of lists (although your example only has one item), so for that you can specify the particular property you are intereste in, for example:
get first item of first item of record_data of testVariable