Mahendra, he is adding DataTable to a Dataset so No need to do
Dataset ds = new DataSet();
In your
getDrugName
function, at time of creating new DataTable object you are passing TableName.
Instead
DataTable drugNameTable = new DataTable("Drug Name");
, you should use
DataTable drugNameTable = new DataTable();
.
By giving table name in DataTable constructor it fixes a table name and next time it will try to add same table name and it started giving error.
Or you can pass Count parameter to your getDrugName code which uses counter in its table name.
Regards
Rushi