SQL JOIN between DataTables in a DataSet

[Guest]

Hello,

Am I correct in thinking that it is currently not possible to perform an SQL
JOIN across multiple DataTables in a DataSet in .NET? I have a typed DataSet
with three relational tables which need to be placed into one flat table,
e.g.:

Table A: PK, Table A Col 1, Table A Col 2...
Table B: PK, FK 1 (Table A PK), FK 2 (Table C PK)
Table C: PK, Table C Col 1, Table C Col 2...

=> PK, Table A Col 1, Table A Col 2, Table C Col 1, Table C Col 2

Currently the only way to resolve this involves embedded for-loops going
down each of the typed relations to get the required data. Obviously
performing one SELECT statement would be far more efficient, but is this
possible here?

I only have access to this DataSet and so am unable to perform the join in
the database before the DataSet is Filled.

Thanks,

Marc

 

[William \(Bill\) Vaughn]

Right. There is (currently) no SQL engine in ADO.NET. That's what's coming
in Orcas.

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[Guest]

Excellent, thanks.

 

[Adrian Moore]

http://www.queryadataset.com

Now supports joining across mulitple datasets and information_schema for
querying dataset metadata such as tables, columns and indexes.

Hope this helps
Ad.

 

[Adrian Moore]

Bill,

Orcas does not provide ad-hoc SQL statements to be executed against the
data. It is also limited to the data in the local process unless you
implement a data provider. Finally, it currently does not support indexing
but I've heard this will be possible by RTM.

The SQL engine which I provide at http://www.queryadataset.com does not have
these limitation when querying datasets or XML documents and it available
today. If you are interested in evaluating it, please download the trial
and try it. It provides a robust, high-performance implemenation which is
in use by over 50 companies today. My ultimate intention is to evolve this
into a soft, real-time, peer-to-peer networked database.

Thanks
Adrian Moore

Microsoft MVP - Windows Networking