How to commit?

Question

Hi there,
I have 3 operations in a function, do I need commit three times or only one time like below?
TIA
Wolf
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          con.setAutoCommit(false);
          String insertStatement = "Insert into dayhistory (s_code, d_code, date, starttime, endtime) select inservice.s_code, inservice.d_code, inservice.date, inservice.starttime, addtime(inservice.starttime,\"1:0:0\") from inservice where hour(timediff("+mt+",starttime))>=1";
          String updateStatement = "update computer set status = 0 where s_code in (select s_code from inservice where hour(timediff("+mt+",starttime))>=1)";
          String deleteStatement = "DELETE FROM inservice where hour(timediff(+"+mt+",starttime))>=1";
          PreparedStatement insertStmt = con.prepareStatement(insertStatement);
          insertStmt.executeUpdate();
          insertStmt.close();
          PreparedStatement updateStmt = con.prepareStatement(updateStatement);
          updateStmt.executeUpdate();
          updateStmt.close();
          PreparedStatement deleteStmt = con.prepareStatement(deleteStatement);
          deleteStmt.executeUpdate();
          deleteStmt.close();
          con.commit();
          con.setAutoCommit(true);

Answer 1

con.setAutocommit(false);
try{
sql stmt1
sql stmt2 ... et etc
(bunch of sql executions)
catch(SQLException e){
con.rollback();
con.commit();
con.setAutoCOmmit(true);Wouldn't you want to put the commit inside the try catch block. What happens when an exception is thrown, the roll back is called and then the commint is called?
Also I believe that the roolback can throw an exception, so you may want to wrap that line in a seperate try catch block.