How to bring the max value add 1 in creation mode

Question

Dear sir:
I have ADF form and when I press on create Button I want on one of the field to bring the maximum number +1, I don't want to use DBSequance because the user should decide if he want the default number or enter new one, also I need if the user enter number already exist the system shows him warning message and make him to write new one.
I use Jdeveloper10g , and adf business component and I used Action in the Create button With this method
public String whenCreatPress() {
//to mahe disable,enabel and rendering for the buttons and the fields
Map session = FacesContext.getCurrentInstance().getExternalContext().getSessionMap();
if (session.get("Render1")==null){
session.put("Render1",true);
session.put("Render2",false);
session.put("Butt1",false);
session.put("Butt2",false);
session.put("Butt3",false);
session.put("Butt4",true);
session.put("Butt5",true);
session.put("Butt6",true);
session.put("Butt7",true);
session.put("displayB",false);
session.put("displayB1",true);
session.put("displayB2",true);
//I have to write the code for Max()+1 hear
}else{
session.put("Render1",false);
session.put("Render2",true);
session.put("Butt1",true);
session.put("Butt2",true);
session.put("Butt3",false);
session.put("Butt4",false);
session.put("Butt5",false);
session.put("Butt6",false);
session.put("Butt7",false);
session.put("displayB",true);
session.put("displayB1",false);
session.put("displayB2",true);
//I have to write the code for Max()+1 hear
return null;
}

Answer 1

John,
What would you recommend then in the following scenario? I need to find a way to insert records into a child table that has a FK relationship with its parent table and a sequence number that increments for each additional record associated with the parent.
For instance, I have a claim with mulitple lines
<PRE>
Claim Id Line sequence Description
1 1 this is for claim 1 line 1 information
1 2 this is for claim 1 line 2 information
1 3 this is for claim 1 line 3 information
2 1 this is for claim 2 line 1 information
2 2 this is for claim 2 line 2 information
</PRE>
I cannot use a sequence here because seqence has to be reset for each new claimid.
Any ideas?
I am using Jdev 11.1.1.1.0 and oracle database and using bc4j
Thanks,