Question

ArrayList queryParms = new ArrayList();
StringBuffer sql = new StringBuffer();
sql.append(
"SELECT A.FLDREC_NUM, " +
"@CHARDATE(A.FLDDATE), " +
"T.FLDDESCR, @DEC(A.FLDLEVEL,3) " +
" FROM @SCHEMAALCOHOL A LEFT OUTER JOIN @SCHEMADRUGCAUS T " +
" ON A.FLDREASON = T.FLDCODE " +
" WHERE A.FLDEMPLOYEE = ? " +
" ORDER BY A.FLDDATE DESC"
);
queryParms.add(new Long(empRec));

1. Can i use HashSet instead of ArrayList above and does it make any sense in terms of performance?.

2. What does the query do, do we need to append the query in StringBuffer. Why can’t i directly add to ArrayList?

Answer 1

In general, you would want to use an ArrayList for query parameters – because the order matters. When you’ve only got a single parameter (as you have here) it’s not an issue – but I’d definitely use a list for consistency.

As for using StringBuffer – you haven’t shown what you’re doing with sql here. If you’re not appending anything else, you could use a simple String… but you wouldn’t be adding it to the ArrayList, as it’s the query itself, not a query parameter.

Finally, I’d recommend using generics, e.g.

ArrayList<Long> queryParameters = new ArrayList<Long>();