Queries with parameters - how do they get migrated?

Question

We are evaluating this migration to move a client off of access and put them into oracle. We use APEX for other things and like it. So, we tried with 3 tables, one query and one report. The tables moved fine, but the query failed. The log showed:
Failed to Convert View <name> unexpected end of subtree: Line 0 Column 0.
I began removing things to determine what was causing it. I finally got it to run when I got rid of the functions like iif, int and val. I think these are causing the issue. But, I still couldn't create the view because of the parameter in the query. Access prompts the user for this value before the query is run, but how would this translate to an Oracle view? And how would the report prompt the user for this value in Apex? Does this convert over automatically?
If I have to rewrite the queries myself, I will. If I do, will that affect importing reports like this into Apex? Any suggestions?
Thanks, Chris

Answer 1

Hi Chris,
Thanks for the updates.
Currently the Oracle SQL Developer Migration Workbench translator does not support the parsing of the IIF function. I believe there is a bug already logged against this & a fix will be available in a future release of the Workbench.
You may find it useful to refer to the following threads discussing alternative handling of queries using the IIF function -
Access Queries with "IIF" function
msaccess parser error
As mentioned in the above postings, one option for you is to use a CASE statement, similar to the following:
SELECT SUM(case when Table1.Week Between 1 And Ending_Week then Table1.Sales else 0 end) TY_Sales_YTD
FROM Table1 ;
If you wished to use such a query to display the resulting value on an Oracle APEX page, this could be implemented as follows:
Note: Assuming that you have migrated the database schema to Oracle & have associated your APEX workspace with that schema.
1. Create a new blank page in your APEX application. Add a new HTML region to your page.
2. Create a "Select List with Submit" item and in its "List of Values Query" field enter syntax similar to the following:
select week d, week r
from table1
order by 1
and set the item name to P1_END_WK. Place the item on your HTML region. This item will act as the parameter in your query.
3. Create a "Display as Text" item and set its Source region to be of type "SQL Query". Paste the following syntax into the items' source value field:
SELECT SUM(case when Table1.Week Between 1 And :P1_END_WK then Table1.Sales else 0 end) TY_Sales_YTD
FROM Table1
and set the item name to P1_SUM. Place the item on your HTML region. This query will return the result based upon the user's selection of value in the P1_END_WK select list item.
4. Add a branch to the page, setting it to branch to itself. Basically when the user selects a value from the P1_END_WK select list, this will submit the page. The branch will redirect the page to itself & in turn update the value held in P1_SUM.
Would this type of implementation work for your application? It's obviously just one option to consider. I hope this helps. If you have any further issues/questions regarding any of the above information or regarding other queries in your MS Access MDB file, please let me know. If you'd like me to take a look at your MDB file, please post your email address so I can contact you directly.
Regards,
Hilary
Message was edited by:
hfarrell