AutoIncrement

Aaron Edwards · February 7th, 2007, 01:37 PM

Hi,

I've got an ID column in a dataTable that has auto-increment set to True. Yet for some reason when I add a new row that column maintains a value of DBNull! What's up with that?

Here is my code:

When Filling the table...

Code:

'First column, "PromoteID" is set as an identity in DB
da.FillSchema(dsTracking, SchemaType.Source)
da.Fill(dsTracking, "Tracking")

When adding a row later on...

Code:

'add a new record to Tracking table
Dim dr As DataRow = dsTracking.Tables("Tracking").NewRow
dr("EmployeeID") = EmployeeID.Text
dr("ChangeDate") = Today
dsTracking.Tables("Tracking").Rows.Add(dr)

When I debug, both dr("PromoteID") is DBNull and so is dsTracking.Tables("Tracking").Rows(...last row...)("PromoteID") after I add dr to the table.

One thing which might be significant is that I'm storing the dataset in the cache, and then retrieving it on postbacks.

Please help? My client is waiting none too patiently.

Aaron

gbianchi · February 7th, 2007, 01:47 PM

hi there...

I never do this in that way.. but don't you have to commit the changes to the db using AcceptChanges??

because you are only seeing the cached data and not the real db data...

HTH

Gonzalo

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Aaron Edwards · February 7th, 2007, 01:53 PM

Hi, thanks for responding.

If I commit the changes using dsTracking.AcceptChanges, then I won't be able to commit them back to the database later.

In this case, seeing the cached data is actually okay.

Thanks.

Aaron

gbianchi · February 7th, 2007, 02:02 PM

but you need to tell the db to add the row so it can produce the autoincrement field...

remember that the datatable is not bounded to the db so it doesn't know that you add a row... if you look at the field definition of the datatable that particular field has only data type, and the auto increment is a db functionality...

HTH

Gonzalo

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Aaron Edwards · February 7th, 2007, 02:16 PM

Really? You're sure? Wow. Is there no way to simulate an AutoIncrement column in a disconnected dataset then?

Aaron

gbianchi · February 7th, 2007, 02:37 PM

almost almost sure...

but we need an sql expert here so he/she can check this out..

HTH

Gonzalo

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