Corrupt Session State? - Apex form posts text value as Null

Question

Recently I've discovered an issue with our Apex installation in which any value chosen as a source for a text field ends up being posted as a null to the database.
We are running APEX version 3.2 within an Oracle 10.2.0.4 database using the Oracle HTTP Server from the 10g companion disk.
At first glance, everything appears to function as expected; I have created a simple table called "oracle_sr" with 2 columns both not null:
SQL> desc capacity.oracle_sr
Name Null? Type
ORACLE_SR_ID NOT NULL NUMBER
TIMESTAMP NOT NULL DATE
Within APEX the form wizard was used to create a form on this table.
After executing the pages and entering a value for the timestamp field I can create records without issue.
The issue arises when I choose a source value for the timestamp field.
Any of the source options result in the same error (including a static value) so I will focus on the SQL Query for the source as:
select sysdate from dual;
This should substitute the system date within the timestamp text field when the page is executed.
As expected, the value appears in the text box but when I submit the form to create the record I receive the error:
ORA-01400: cannot insert NULL into ("CAPACITY"."ORACLE_SR"."TIMESTAMP")
I have been working with APEX for quite some time and have successfully used this technique in many applications but just started to see this error over the past few days. What is particularly odd about this message is that default "not null" validations created by the form wizard sees the timestamp filed as having a value. The session state information included below is reporting a value yet the database is throwing the ORA-01400.
Has anyone experienced a similar issue? I've spent a fair amount of time trying to research this issue but cannot seem to find any similar posts.
I have included the debug output from my test page, from what I can see, there does seem to be a value associated with the timestamp filed:
0.00: A C C E P T: Request="CREATE"
0.00: Metadata: Fetch application definition and shortcuts
0.00: NLS: wwv_flow.g_flow_language_derived_from=FLOW_PRIMARY_LANGUAGE: wwv_flow.g_browser_language=en-us
0.00: alter session set nls_language="AMERICAN"
0.00: alter session set nls_territory="AMERICA"
0.00: NLS: CSV charset=WE8MSWIN1252
0.00: ...NLS: Set Decimal separator="."
0.00: ...NLS: Set NLS Group separator=","
0.00: ...NLS: Set date format="DD-MON-RR"
0.01: ...Setting session time_zone to -06:00
0.01: Setting NLS_DATE_FORMAT to application date format: DD-MON-RR
0.01: ...NLS: Set date format="DD-MON-RR"
0.01: Fetch session state from database
0.01: ...Check session 2303701116904676 owner
0.01: Setting NLS_DATE_FORMAT to application date format: DD-MON-RR
0.02: ...NLS: Set date format="DD-MON-RR"
0.02: ...Check for session expiration:
0.02: ...Metadata: Fetch Page, Computation, Process, and Branch
0.02: Session: Fetch session header information
0.02: ...Metadata: Fetch page attributes for application 109, page 50
0.02: ...Validate item page affinity.
0.02: ...Validate hidden_protected items.
0.03: ...Check authorization security schemes
0.03: Session State: Save form items and p_arg_values
0.03: *...Session State: Save Item "P50_ORACLE_SR_ID" newValue="" "escape_on_input="N"*0.03: *...Session State: Save Item "P50_TIMESTAMP" newValue="26-MAY-09" "escape_on_input="N"*
0.03: ...Session State: Save "P0_CURRENT_PERSONNEL_ID" - saving same value: "1"
0.03: ...Session State: Save "P0_OFFSET" - saving same value: "0"
0.03: ...Session State: Save "P0_ACTIVE_WEEK" - saving same value: "24-MAY-09"
0.03: Processing point: ON_SUBMIT_BEFORE_COMPUTATION
0.03: Branch point: BEFORE_COMPUTATION
0.03: Computation point: AFTER_SUBMIT
0.03: Tabs: Perform Branching for Tab Requests
0.03: Branch point: BEFORE_VALIDATION
0.03: Perform validations:
0.03: ...Item Not Null Validation: P50_TIMESTAMP
0.04: Branch point: BEFORE_PROCESSING
0.04: Processing point: AFTER_SUBMIT
0.04: ...Process "Get PK": PLSQL (AFTER_SUBMIT) declare function get_pk return varchar2 is begin for c1 in (select ORACLE_SR_SEQ.nextval next_val from dual) loop return c1.next_val; end loop; end; begin :P50_ORACLE_SR_ID := get_pk; end;
0.04: ...*Session State: Saved Item "P50_ORACLE_SR_ID" New Value="6"*
0.04: ...Process "Process Row of ORACLE_SR": DML_PROCESS_ROW (AFTER_SUBMIT) #OWNER#:ORACLE_SR:P50_ORACLE_SR_ID:ORACLE_SR_ID|IUD
0.04: Show ERROR page...
0.04: Performing rollback...
ORA-01400: cannot insert NULL into ("CAPACITY"."ORACLE_SR"."TIMESTAMP")
Unable to process row of table ORACLE_SR.
Return to application.
Any thoughts would be appreciated.
Thank you,
Justin.

Answer 1

If you changed the Source Type of an item from Database Column to something else, then it cannot participate in the Automated Row Fetch/Automatic Row Processing (DML) choreography. You should leave the Source Type as it was and change the item's Default Value to populate it when the ARF process fetches a null for the column.
Scott