How to pass set 'Relation' between blocks dynamically..Pls help

Question

Dear all,
Best wishes,
Please help me to find solution for this..
I have two forms A and B. Form A will pass 4 parameter to form B so that B will fetch the details. till this everry thing is fine..
Form A -- > Uses Table A --> col1,col2,col3,col4
Form b ----> Uses Table B ---> col1,col2,col3
table a col1 = table b col1
a col2 = b col2
a col3 = b col3
a col4(already exist) = b.col4(newly added) (no data exist for col4 table B for current records but will have future records)
Form A passes all these 4 col as parameter to form B.
But actual problem is for all new records (will have all the relation records i.e. Table A col1,col2,col3,col4= Table B col1,col2,col3,col4) so existing relation works fine Form B while fetching the data ( I manully edited relation between these two tables by adding Table A.col4=TableB.col4)
How ever this relation is giving problems for EXISTING RECORDS in Table B which does not which is not having corresponding equal value to Col4 in Table A.
so now scenario is if i remove that addition I made , THEN IT ONLY WORKS FOR EXISTING RECORDS
and
if i keep update relation between block (updated one including col4) then IT ONLY WORKS FOR NEW RECORDS since col4 parameter passes as null to form B then since no records in Form B.
what my idea is to pass 'relation' dynamically creating relation for old and new records.
like "telling form B to check -- if Table B.col4 is null where TableA.col1 = TableB.col then -- opt for relation which DOES NOT INCLUDE a.col4=b.col4 in relation statement
or
if Table B.col4 is notnull (Table having correspoiding records) where TableA.col1 = TableB.col then -- opt for relation which INCLUDE a.col4=b.col4 in relation statement
Sorry for long post..hope i am clear on my requirements..
Any suggestions are welcome...
thanks in advance
Prasanth

Answer 1

Prasanth,
Were I in your situation, I would push back on the author of the requirement and inform them that the data in Table 1 must be updated to conform with new requirement. This eliminates any DDL change to the tables and it is not unreasable to require a DML change to the data to support a "New" requirement. If the author of the requirement still will not see reason and wants you to make it work as is, then it could be made to work as is, but it will require a complete redesign of the Form and a complete regression test of the form to ensure the new Form process doesn't break functionality or have unexpected side-affects. Provide development time and cost estimates so the "author" can determine the cost effectiveness of the options.
As to the options, you could make this work using a From Clause Query based block or a Procedure based block. Both options will allow you to use NVL or DECODE, but will require you to handle any Forms DML manually using the On-Ins, On-Upd and On-Del triggers. Both options will also allow you to use the Relationship feature of data blocks.
If you have access to My Oracle Support, take a look at the following documents:
<ul>
<li>How to use Fro m Clause Query in Forms [ID: 69884.1]
<li>Basing a Block on a Stored Procedure - Sample Code [ID: 66887.1]
<li>Master/Detail Relationship Based on Stored Procedures [ID: 124650.1]
</ul>
If you don't have My Oracle Support access, take a look at this URL for some examples:
Oracle Forms 10g release 2 : Demos, Tips and Techniques and scroll to 2.3.2 Block based on stored procedures.
Hope this helps,
Craig B-)
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