:VARIABLE_NAME and v('VARIABLE_NAME') have different values

Question

A basic question ...
I have the following ... (including some debug stuff) ...
IF (:P3_PE_REQ_STATE = 'NEW') THEN
:P3_PE_REQ_STATE := 'DRAFT';
insert into debug_table values(null,v('P3_PE_REQ_STATE'));
insert into debug_table values(null,:P3_PE_REQ_STATE);
commit;
END IF;
The DEBUG_TABLE shows two different values ... with v('P3_PE_REQ_STATE') = 'NEW' and :P3_PE_REQ_STATE = 'DRAFT'
Why would these be different?

Answer 1

In ajc's block, v('P3_PE_REQ_STATE') obtains the value from the PL/SQL package state copy of session state in the database session. This is the pre-updated value. The assignment statement with :P3_PE_REQ_STATE on the left-hand side changes the value of the bind variable, which may be subsequently altered/referenced as a bind variable to the extent the name remains in scope for the duration of the dynamic execution of the block. At the end of the block, the final value of any bind variables corresponding to page or application items and whose pre- and post-execution values are different are written to the session state tables and committed (using the same code invoked by HTMLDB_UTIL.SET_SESSION_STATE). At that point the package-state copy of session state is also updated so that subsequent references using the v function will get the updated value.
Scott