Problem to record website user session in db

Question

I want to record user session of my website in database. I created the following table,sequence and trigger.
when the user will be connected after verification it will be inserted into db till here its ok but problem is logout when the user will logged out then what query I can make? I want that my query get the last s_id of the last co_id and insert value in end_date
Oracle 9i
create table co_session(
s_id number(14) primary key,
co_id number (9) constraint session_fk1 references company(co_id),
start_date timestamp(0) default sysdate,
end_date timestamp(0));
create sequence session_pk_seq
start with 1 increment by 1;
create or replace trigger session_pk_trig
before insert on co_session
referencing new as new
for each row
begin
select session_pk_seq.nextval into :new.s_id from dual;
end;
/

Answer 1

That depends... many web servers/application servers make use of a database connection pool.
They open a pool of connections to Oracle. One such pooled connection can be used and re-used many times. And for different web front-end users.
Generally speaking, it makes very little sense to create any type of logon/logoff triggers for web sessions.
As the application server deals with user authentication and user state and user sessions, the application server should deal with "recording" these sessions against the database.
And this is as true of APEX as of JBoss or Weblogic. APEX is a PL/SQL Application Server running inside the Oracle database. It too does not use database triggers to "record sessions" - it does this "recording" itself in the application (PL/SQL) layer and not the SQL/database layer.
What you describes sounds to me like a flawed approach dealing with stateless clients in a 3 tier architecture.