Question

Say i’m dealing with 10 library cards, each card has customer values (eg. member number, member name …) and I need to update a value for each card.

If i want to grab all ten from the database but only want to update each row one at a time, is there an alternative to a cursor? I know a while loop might work but how would I be able to grab one row every time it loops until I am done with all 10 cards?

Answer 1

Don’t need to use cursors. I use this most of the time:

declare @uid int -- this is the type unique index on the table you're updating

-- Copy out the unique ids of the rows you want to update to a temporary table
select uid into #temp from customers -- you can use a where condition here

-- Loop through the rows of the temp table
while exists (select 1 from #temp)
begin
  set rowcount 1
  select @uid = uid from #temp -- pull one uid from the temp table
  set rowcount 0
  delete from #temp where uid = @uid -- delete that uid from the temp table

  -- Do something with the uid you have
  update customers set name = 'Joe Shmoe' where uid = @uid

end