Hierarchical tree in web forms 10g - form freezing

Question

I have an application with an hierarchical tree on one of the forms - the application worked fine as client/server back in forms 6 but now that it is web enabled in 10g there are problems with the tree causing the form to freeze, then the entire application has to be closed. It doesn't seem to matter if you are selecting a node or creating a new node both have caused the form to freeze. It doesn't happen all of the time but it seems that the longer the application has been in use the more it starts to freeze. Any ideas? Is there a known problem with trees in web forms? Thanks
Joanne

Answer 1

At the root of my tree is a patient (I work in the health care industry) and then for that patient there are clinic visits, surgeries, etc (there are 16 nodes at this level). and under each of these are dates when the visits occured (there can be an unlimited number of nodes at this level). This is some of my code for populating the tree:
if :GLOBAL.patient_seq is not null then
-- turn the tree on
set_item_property('tree_block.tree_item', ENABLED, PROPERTY_TRUE);     
set_item_property('tree_block.tree_item', NAVIGABLE, PROPERTY_TRUE);          
lv_tree_id := find_item('TREE_BLOCK.TREE_ITEM');     
--refresh the tree back to it's original state from the database                          
Ftree.Set_Tree_Property(lv_tree_id,
     Ftree.RECORD_GROUP,
     FIND_GROUP('TREE_GROUP'));
-- create the clinic visits branch
wcchn_tree_items_pkg.get_visits(lv_visit_table, :global.patient_seq);
for lv_counter in 1.. lv_visit_table.count loop
lv_site := wcchn_locations_pkg.get_location_code(lv_visit_table(lv_counter).site);
create_visit_node( lv_visit_table(lv_counter).visit_date || ' - ' || lv_site,
     lv_tree_id,
lv_visit_table(lv_counter).seq_nr);
end loop;
Below is the procedure referred to in the above segment of code:
PROCEDURE CREATE_VISIT_NODE (pi_date IN VARCHAR2, pi_tree_id IN ITEM, pi_seq IN NUMBER) IS
lv_return_value NUMBER;
lv_node_value varchar2(100);
lv_search_node FTREE.node;
BEGIN
lv_search_node:=FTREE.Find_Tree_Node(pi_tree_id,                              'CLINIC VISITS',                         FTREE.FIND_NEXT,                         FTREE.NODE_LABEL,                         FTREE.ROOT_NODE,                         FTREE.ROOT_NODE);
lv_node_value:='G' || to_char(pi_seq);
if :GLOBAL.ACTION_INDICATOR = 'INSERT' then
          lv_return_value:=FTREE.Add_Tree_Node(pi_tree_id,                    lv_search_node,                         FTREE.PARENT_OFFSET,                          1,                                    FTREE.LEAF_NODE,                          pi_date,                                   NULL,                                    lv_node_value);
else
          lv_return_value:=FTREE.Add_Tree_Node(pi_tree_id,                              lv_search_node,                          FTREE.PARENT_OFFSET,                          FTREE.LAST_CHILD,                          FTREE.LEAF_NODE,                          pi_date,                                   NULL,                                    lv_node_value);
end if;
     FTREE.Set_Tree_Node_Property(pi_tree_id,                              lv_search_node,                              FTREE.NODE_STATE,                         FTREE.EXPANDED_NODE);
END;