In dbaccess (for me, Informix 7.31), if I have the following
statements:

set lock mode to wait;
update table set column = 'X' where columnPK = 1;
update table set column = 'X' where columnPK = 2;
update table set column = 'X' where columnPK = 3;

I am under the assumption that each trasnaction is committed after the
semicolon - so in effect, I am making three distinct trasnactions to
the log (and the buffer). However, my colleague believes this would
be one transaction - so if the above statement repeated up to 15,000,
I would be locking out 15k rows. Is he correct?