Need Help in creating this trigger

Question

I need your help to create this trigger. I need to set the default fl in this table depending on various conditions:
If there is only one indvl with end date as null then set the default_pk column for that indvl as 'Y'
ELSE
If there are multiple indvl_pks in this table with NULL end date then set the default_fl column to 'Y' for the indvl_pk with the earliest start date .
ELSE if there are multiple indvls with same start date then set the dflt_fl to 'Y' with the minimum br_pk
I am unable to get this to work due to the mutating trigger problem.
For example in this one rows with emplt_pk with 1001 and 1003 will be set to 'Y'.
create table emplt
emplt_pk number,
indvl_pk number,
start_dt date,
end_dt date,
lct_fl char(1),
sup_fl char(1),
br_pk number,
nro_pk number,
default_fl
char(1) default 'N' );
INSERT
INTO emplt
values(1001, 101, to_date ('01-01-2005', 'MM-DD-YYYY' ), NULL, 'Y','N' ,123,NULL,NULL );
INSERT INTO emplt values(
1002, 101, to_date ('02-01-2005', 'MM-DD-YYYY' ), NULL, 'Y','N' ,NULL,0001,NULL );
INSERT INTO emplt values(
1003, 102, to_date ('02-01-2005', 'MM-DD-YYYY' ), NULL, 'Y','N' ,NULL,0001,NULL );
Thanks in advance

Answer 1

the Easy Tabs could be useful for your requirement
http://usermanagedsolutions.com/SharePoint-User-Toolkit/Pages/Easy-Tabs-v5.aspx
/blog
twttr @esjord