Need some explanations on updating database through dataset

[panadoll]

Hi,

I encountered this problem which i manage to solve but I need to know the reason why.

I have 3 tables.
Table 1: Batch table
PK: Batch No

Table 2: Invoice Table
PK: Batch No
: Invoice No

Table 3: Detail table
PK: Batch No
: Invoice No
: Line No

These tables all have relationship i.e. Batch -> Invoice -> Detail. These are all in 1 dataset and I have 3 oledataadapter for ea of the table.

They are all binded to the the database with detail table as a datagrid.

when i try to save the 3 tables using 1 getchanges() statement. However, the detail table is not updated into the database using the adaptor.update statement.
e.g

Dim dsChanges As New DataSet
dsChanges = DS_DetailGrid.GetChanges()

Try
If Not dsChanges_Batch Is Nothing Then
If TableName = "INVBATCH" Or TableName = "" Then Database.UpdateDataSet(OleDbAdpt_InvBatch, dsChanges)
If TableName = "INVHEADER" Or TableName = "" Then Database.UpdateDataSet(OleDbAdpt_InvHeader, dsChanges)
If TableName = "INVDETAIL" Or TableName = "" Then Database.UpdateDataSet(OleDBAdpt_InvDetail, dsChanges)
End If
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try


in the end, after several tries, I found out that the solution to my problem is to create 3 getchanges() statement and ea of the 3 data adapters updating the dataset. then my detail table is updated into the database.
e.g
Dim dsChanges_Batch As New DataSet
Dim dsChanges_Header As New DataSet
Dim dsChanges_Detail As New DataSet

dsChanges_Batch = DS_DetailGrid.GetChanges()
dsChanges_Header = DS_DetailGrid.GetChanges()
dsChanges_Detail = DS_DetailGrid.GetChanges()

Try
If Not dsChanges_Batch Is Nothing Then
If TableName = "INVBATCH" Or TableName = "" Then Database.UpdateDataSet(OleDbAdpt_InvBatch, dsChanges_Batch)
If TableName = "INVHEADER" Or TableName = "" Then Database.UpdateDataSet(OleDbAdpt_InvHeader, dsChanges_Header)
If TableName = "INVDETAIL" Or TableName = "" Then Database.UpdateDataSet(OleDBAdpt_InvDetail, dsChanges_Detail)
End If
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try


Please enlight me on what is the problem and solutions and does having 3 getchanges() statement have any ill effect?

Thanks U!