Question

I have three methods that, together, save a node to the database. Currently, this does not achieve the desired effect of not committing the changes unless all the writes are successful.

    conn.setAutoCommit(false);
    writeNodeTable(node, newNodeNID);
    writeContentTypeBoutTable(node, newNodeNID);
    writeTerms(node, newNodeNID);
    conn.commit();

If there is a problem (such as an uncaught exception is thrown) in the second or third method, I’d like to roll back all the changes. Is there some way I can use transactions to do this?

This is one such DB writing function:

private void writeTerms(DrupalNode node, int newNodeNID) throws SQLException {
    String sql = "INSERT INTO term_node (nid, vid, tid) VALUES (?, ?, ?)";
    PreparedStatement prep = conn.prepareStatement(sql);
    prep.setInt(1, newNodeNID);
    prep.setInt(2, newNodeNID);

    String schoolName = termHelp.schoolOfAgainst(node.get(BoutField.against));
    prep.setString(3, schoolName);

    prep.execute();

    String fencerName = termHelp.fencerOfAgainst(node.get(BoutField.against));
    prep.setString(3, fencerName);
    prep.execute();
    prep.close();
}

Answer 1

You can use rollback method in Connection interface.
http://java.sun.com/j2se/1.5.0/docs/api/java/sql/Connection.html#rollback()

Also you have to set setAutoCommit to false and call commit and rollback methods as appropriately.