How to insert data in Oracle table with virtual columns? - vb.net

Question

I have a .Net application that loads a datatable from an oracle Database. The table contains a virtual column.
When I'm inserting a new row in datatable, it says :
Insert INSERT operation disallowed on virtual columns
I do understand this error but I don't know how to skip the virtual columns when saving data back to the database.
Here is my code :
Dim Command As OracleCommand
Dim TempDataAdapter As OracleDataAdapter
Dim DataSet = new DataSet
Dim Name = "MyTable"
Dim TempDataAdapter As OracleDataAdapter
Dim DataTable as DataTable
'The connection is defined somewhere else...
Command = New OracleCommand("MyTable", Me.Connection)
Command.CommandType = CommandType.Text
TempDataAdapter = New OracleDataAdapter(Command)
'Fill the table from the database
TempDataAdapter.FillSchema(DataSet, SchemaType.Source, Name)
DataTable = DataTable = DataSet.Tables(0)
And the code for saving data back to database :
TempDataAdapter.Update(DataTable)
After the creation of the datatable, I tried deleting the virtual column from the datatable :
DataTable.Columns.Remove(DataTable.Columns("MyVirtualColumn"))
But when saving data back to the database, it returns the same error.
Can anyone help please ?
Cheers,

Answer 1

If you are not trying to populate or query the virtual column, can you create a view on that table that excludes the virtual column and work with that view.

Answer 2

When you insert data into table with virtual columns then you must list columns, i. e. you must not use
Insert into table_x values (x, y, z)
but
Insert into table_x (col1, col2, col3) values (x, y, z)
Write your .net statements accordingly. If you try to update with DataTable then you can use a view which excludes the virtual columns:
CREATE OR REPLACE VIEW V_MyTable AS
SELECT col1, col2 -- skip virtual_col3
FROM MyTable;
In case you like to select virtual columns but skip them for INSERT (or UPDATE) you can create a view with a INSTEAD OF Trigger. Would be like this:
CREATE OR REPLACE VIEW V_MyTable AS
SELECT col1, col2, virtual_col3
FROM MyTable;
CREATE OR REPLACE TRIGGER IO_MyTable
INSTEAD OF INSERT OR UPDATE ON V_MyTable
FOR EACH ROW
BEGIN
IF UPDATING THEN
UPDATE MyTable SET
col1 = :NEW.col1,
col2 = :NEW.col2
WHERE primary_key_col = :OLD.primary_key_col;
ELSIF INSERTING THEN
INSERT INTO MyTable (col1, col2) VALUES (:NEW.col1, :NEW.col2);
END IF;
END;