How select from 2 ADO.NET DataTables?

10 Mar 2006 5:31 AM

Ronald S. Cook

Let's say I have 2 ADO.NET DataTables (tblAuthor and tblBook) within an
ADO.NET DataSet (dstPublish).

tblAuthor has DataColumns AuthorID and AuthorName, tblBook has DataColumns
BookID, BookTitle, AuthorID (assume a book can be written by only one
author).

tblAuthor

---------

1 Ayn

2 Jim

3 Sue

tblBook

-------

10 Fountainhead 1

11 Atlas Shrugged 1

12 Moby Dick 2

I want to create a list of all books with their associated author name.

FountainHead Ayn

Atlas Shrugged Ayn

Moby Dick

This is a breeze in SQL for me, but I'm not sure how to go about using
ADO.NET DataTables. Do I need a DataRelation, or is it just a matter of
having a for loop within a for loop, or is it something else?

Thanks,

Ron

10 Mar 2006 7:23 AM

Truong Hong Thi

>Do I need a DataRelation, or is it just a matter of
>having a for loop within a for loop

You can create a DataRelation. The DataRow has methods for navigation
along the data relation like GetParentRows, GetParentRow, GetChildRows,
etc. Something like this:

dataSet.Relations.Add(tblAuthor.Columns["ID"],
tblBooks.Columns["AuthorID"]);
Change the column names appropriately.

foreach (book row in tblBookx)
{
Row authorRow = row.GetParentRow();
}

You still have to loop, but it simplifies parent looking-up by removing
the inner loop.

Thi