Devart Forums

Dear Crlab-Team,

I have a problem with ODAC-Master-Detail linking and I hope you can help me.

Here's how to hit that problem:

1) Open the "MasterDetail" Demo in the ODAC win32 demos
2) Change quMaster like this:
SELECT d.DeptNo as myAliasDeptNo, D.*,RowId FROM Dept D
3) Change quDetail like this:
SELECT e.DeptNo as myAliasDeptNo, E.*,RowId
FROM Emp E
4) Select quDetail in the Objectinspector and edit its MASTERFIELDS property
5) => in the Dialog link the two "myAliasDeptNo" and save the whole thing

Now if I run the demo, I get an "ora-00904 invalid column name".


The problem is that ODAC is building a dynamic WHERE clause with the
aliased field names, which leads to an invalid sql-statement.

Of course in this demo, the alias-stuff is not needed at all, but there
are situations, where aliasing field names is essential.

Please find the modified MasterDetail-project here:
http://www.waeberd.ch/files/MasterDetaildw.zip

Any hint is very welcome, thanks a lot!

Best regards,

Daniel

You should either specify actual names of the fields in the DetailFields property or use local Master/Detail relationship.

Hi,

Thanks for your quick answer!

Challenger wrote:You should either specify actual names of the fields in the DetailFields property ...

This doesn't work for prefixed fieldnames like "d.DeptNo". ODAC wants to build a parameter using this name and the "." makes this parameter name invalid. In my case, prefixing the field name is necessary to avoid ambiguously named fields.

Challenger wrote:... or use local Master/Detail relationship.

you mean resolve the master-detail relationship by putting everything into one single query? Would be a workaround.

Regards, Daniel

Such code works without any problems: Or am I missing something?
Another approach is to set the MasterSource property of the Detail dataset, clear the MasterFields and DetailFields properties and set SQL in the following way: For information about local Master/Detail please refer to ODAC help (TOraDataSet.Options.LocalMasterDetail property).

Thank you, your solutions work fine! The second solution also works in the FastReport wrapper of the ODAC-queries, where the problem really came from.

My problem was that I was trying to link the fields only using the property editor, which has less possibilities!

EDIT:
as I am still using ODAC 5.50, the LocalMaterDetail option does not exist yet. Time for upgrading I guess

Problem should be solved, otherwise I will come back!

Thanks again!

Daniel