In my code, I want to the following two queries as a trasaction. If any
of the two queries failed, the database will roll back both queries.How
to make two queries as one trasaction?

// will the code below regard query1 and query2 as trasaction?

query1 = "delete from table1";
query2 = "insert into table1 values ("a1, "a2);

statement1.executeQuery(query1);
statement1.executeQuery(query2);

conn.commit();

// If I don't issue a commit() explictly, will the above two queries be
commited automatically?

Thanks a lot!