How to change delete order?

Question

Hello,
I have classes C, C1, C2. C has private owned 1-N mapping to C1 and private owned 1-N mapping to C2. C1 has 1-1 mapping to C2.
Assume c has c1 and c2, c1 has c2. When I save c, TopLink inserts c, then c2, then c1. Now I remove c1 and c2 from c (from private owned collections) and save c. TopLink tries to delete from database c2 first - I get
"integrity constraint violated - child record found".
Of course it is found - I would like TopLink to remove c1 first, then c2. Why are DELETE statements executed in the same order like INSERT statements? How can I change that order?
Thanks

Answer 1

I'd like to share one possible workaround. It seems that the order of delete operations depends on the order of mappings in descriptor (attributes seems to be sorted alphabetically in project XML generated in TopLink workbench). So I did something like this (in afterLoad method) to ensure the correct order of DELETE operations.
DatabaseMapping mapping1 = pDescriptor.getMappingForAttributeName("att1");
DatabaseMapping mapping2 = pDescriptor.getMappingForAttributeName("att2");
DatabaseMapping mapping3 = pDescriptor.getMappingForAttributeName("att3");
DatabaseMapping mapping4 = pDescriptor.getMappingForAttributeName("att4");
if (mapping1 != null) {
pDescriptor.removeMappingForAttributeName("att1");
pDescriptor.addMapping(mapping1);
if (mapping2 != null) {
pDescriptor.removeMappingForAttributeName("att2");
pDescriptor.addMapping(mapping2);
if (mapping3 != null) {
pDescriptor.removeMappingForAttributeName("att3");
pDescriptor.addMapping(mapping3);
if (mapping4 != null) {
pDescriptor.removeMappingForAttributeName("att4");
pDescriptor.addMapping(mapping4);
}