DataSet.Clear()

  • Thread starter Thread starter mick
  • Start date Start date
M

mick

I`ve been trying to get to know ADO.net lately and I wonder if anyone can
explain why the following does not work -

myDataSet.Clear();
myDataSet.AcceptChanges();
myTableAdapter.Update(myDataSet);

If you clear the dataset and then do the update shouldnt the database be
cleared as well. When I tried this the contents of the database are still
there when I rerun my app.

What I ended up doing was iterating throw the dataset and deleting row by
row but I`m curious why the above doesnt work.

TIA,

mick
 
In your case Clear removes all the information from *Dataset* thus Update
won't do anything. Update does its things based on the rows in their
RowState.
 
Miha Markic said:
In your case Clear removes all the information from *Dataset* thus Update
won't do anything. Update does its things based on the rows in their
RowState.
Click to expand...

I`ve been reading a bit more and would just like you confirm that I
understand it correctly -

When I use Clear on the DataSet it actually clears all of the entries but if
I use Delete it just "marks" entries for deletion but does not actually
perform any deletion until the update. Is this correct?

mick
 
I`ve been reading a bit more and would just like you confirm that I
understand it correctly -

When I use Clear on the DataSet it actually clears all of the entries but
if I use Delete it just "marks" entries for deletion but does not actually
perform any deletion until the update. Is this correct?
Click to expand...

Yes, it will mark existing rows with RowState = Deleted. If the row doesn't
exist in database (it has been added in memory) it will be removed.

HTH,
 
Miha Markic said:
Yes, it will mark existing rows with RowState = Deleted. If the row
doesn't exist in database (it has been added in memory) it will be
removed.
Click to expand...

Thanks Miha.

mick
 
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