count child table rows

melvik · January 22nd, 2004, 10:53 AM

Dear all, let me ask something fast.
when we wanna count a dataSet Rows created by DataAdapter we use

Code:

dataSet11.Table1.Rows.Count

its ok!
But imagine u've created a realtion using IDE in ur Dataset that [u]PID</u> in Table1 is a perent Col for [u]PID</u> in Table2.
Now u wanna count child table's rows?! what code u'll use?! Thank you.
A problem is hard till it hasnt solved!

Always:),
Hovik Melkomian.

CrazyLegsCooper · January 23rd, 2004, 05:02 PM

DataSet dsData;

dsData.Tables[0].ChildRelations["RelationName"].ChildTable.Rows.Count;

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melvik · January 24th, 2004, 03:35 AM

tnx for ur reply dear:
but its doesnt count the related rows in detail! I could count the whole rows before. my problem is : counting related rows in [u]Detail Table</u> not the whole!

hope to hear new ideas.

Always:),
Hovik Melkomian.

Imar · January 24th, 2004, 05:05 AM

Hi Melvik,

You can take a look at the GetChildRows method of the DataRow object. It returns an Array of DataRows that are related to the original DataRow. You can then use the Length property of the Array to get the number of items.

Cheers,

Imar

---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.

melvik · January 24th, 2004, 09:53 AM

Ok tnx it works now, but working witgh this is pretty hard;) do u have any other idea to work with Data in [u]realed table</u>?!

Always:),
Hovik Melkomian.

Imar · January 24th, 2004, 12:17 PM

Yeah, true. It's not as easy or intuitive as you'd like. Then again, it is a *lot* easier than the "old skool" data shaping that Microsoft had for things like this in ADO ;)

Usually I don't use these kind of relations in my dataset. If acceptable (performance wise), I fire a sub query for the related records. Just pass a simple select statement with the ID of the parent record.

However, when you're displaying lots of parent record with their child records (like a DataGrid that displays a nested grid with the child records), this may not be applicable (too many database operations). In that case, using relations is a good way to go. Alternatively, you can create a global DataSet object, store a few DataTables in them and use some filtering techniques to get the related records. But this is, IMO, about as difficult as using the DataRelations ;)

Cheers,

Imar

---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.

melvik · January 25th, 2004, 01:39 AM

Dear Imar:
tnx for ur comments. As I said its not easy to manage, but better than ADO as u said. So i guess using this way would be not better but good. I guess using ur second way (get child info by passing Master ID) would make LAN trafic. So i pefer to manage it once but use it many. anyway tnx for reply & ...

Always:),
Hovik Melkomian.