Entity Object and Seqence

Question

There is a confusion about DBSequence in Entity Object. I've defined an entity object named Employee and its primary key is Gkey. I've chosend DBSequence as its attribute type (Update While New) and overode doDML method as follows:
<code>
protected void doDML(int operation, TransactionEvent e) {
if (operation == DML_INSERT) { 
SequenceImpl seq =
new SequenceImpl("seq_employees_gkey", getDBTransaction());
Integer n = new Integer(seq.getSequenceNumber().intValue());
super.setAttribute(GKEY, new DBSequence(n));
super.doDML(operation, e);
</code>
Its working fine. Whenever I insert a new row in my JClient form, Gkey fields shows blank and when I commit the transaction, next seqence no. automatically comes in.
But when I use Integer or Long as the data type of Gkey instead of DBSequence it didn't make any difference. and was working fine. So what is the exact purpose of DBSequence ?
Secondly, I defined a child Entity Object for the above EO. I defined a ParentGkey column and defined its attribute type Integer and in parent EO, GKey data type was defined as DBSeqeunce. So when I map Parent's Gkey agains Child ParentGKey column to define association, assocation wizard gives a mismatch attribute type error because parent's attribute type was DBSequence and Child type was Integer.
Regards
Aamir

Answer 1

Dear Shailesh,
I didn't override create() method, I overrode the doDML method. I've come to know, by reading previous postings, taht although DBSequence relies on database trigger but overrding doDML method is an alternative to database trigger.
However what I asked here is that JDev team says that framework assigns a unique temporary value to the field that has DBSequence domain, then why I dont see this temporary value in Tester and in my JClient form.The tests I've run with DBSequence does show the negative/temporary DBSequence value in the tester. Do you see the attribute with no-value in the tester or the attribute does not show up at all - which would be the case if the attribute's control-hint indicates it should be a hidden field.
Second thing I asked is that if the field using DBSequence has to be referred as a foreign key in an association then what should be the type of this field in the child EntityObject. If we set this field in child EO as Integer it gives a type mismatch error.That was a bug in JDev 903P. Should be fixed in JDev 903 production.
Hope you will understand my question.
Muhammed Aamir