Regarding object_id in Oracle

Question

I have created a table TEMP_TAB and created 3 triggers on TEMP_TAB table.
Triggers names are trig1, trig2 and trig3.
Now when I query in dba_objects, I found below object_id for respective triggers.
trig1 object id is 374841
trig2 object id is 374857
trig3 object id is 374887
My question is how the object_id are assigned to a particular object in oracle?
Now I have dropped trig1 and recreated the same trigger, with same trigger name (trig1). I can see the object_id did not changed. Why? As we know object_id is primary key.
when I query in dba_objects, I found below object_id for respective triggers.
trig1 object id is 374841
trig2 object id is 374857
trig3 object id is 374887
I user oracle 11g Release 11.1.0.7.0.
Thanks

Answer 1

Something strange is definately on.
The OBJECT_ID for the table changes, but for the trigger it is reused.
BANNER                                                                          
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production    
PL/SQL Release 11.2.0.1.0 - Production                                          
CORE     11.2.0.1.0     Production                                                        
TNS for Solaris: Version 11.2.0.1.0 - Production                                
NLSRTL Version 11.2.0.1.0 - Production    
select object_id,object_name from user_objects where object_name  in ('T1','TRIG1'); 
OBJECT_ID              OBJECT_NAME                                                                                                                     
create table t1 (col1 number);
create trigger trig1
  before insert on t1
  for each row
  begin
   null;
  end;
table T1 created.
TRIGGER trig1 compiled
select object_id,object_name from user_objects where object_name  in ('T1','TRIG1'); 
OBJECT_ID              OBJECT_NAME                                                                                                                     
95352                  T1                                                                                                                              
95350                  TRIG1                                                                                                                           
drop trigger trig1 ;
drop table t1;
trigger TRIG1 dropped.
table T1 dropped.
select object_id,object_name from user_objects where object_name  in ('T1','TRIG1'); 
OBJECT_ID              OBJECT_NAME                                                                                                                     
create table t1 (col1 number);
create trigger trig1
  before insert on t1
  for each row
  begin
   null;
  end;
table T1 created.
TRIGGER trig1 compiled
select object_id,object_name from user_objects where object_name  in ('T1','TRIG1'); 
OBJECT_ID              OBJECT_NAME                                                                                                                     
95353                  T1                                                                                                                              
95350                  TRIG1                                                                                                                           
drop trigger trig1 ;
drop table t1;
trigger TRIG1 dropped.
table T1 dropped.
create table t1 (col1 number);
create trigger trig1
  before insert on t1
  for each row
  begin
   null;
  end;
table T1 created.
TRIGGER trig1 compiled
select object_id,object_name from user_objects where object_name  in ('T1','TRIG1'); 
OBJECT_ID              OBJECT_NAME                                                                                                                     
95354                  T1                                                                                                                              
95350                  TRIG1