Update query in C# .

Hi,

If I were you, if possible according to your application's requirements, I would create a stored procedure to make both changes. Inside stored procedure, write a query to update "Invoice table" and then "Stock Table".

This solution, from my view, is cleaner and maintainable (only use one object to contain code) than using triggers, but it's up to you.

The pseudocode would be similar to:

CREATE PROCEDURE YourProcedureName
    @param1 -- Your Params
    ...
    @paramN,
    @Quantity
AS
BEGIN
	SET NOCOUNT ON;

    /* Query to insert into G_Invoice */
    insert into G_Invoice 
    values(@param1,..,@paramN,...,@Quantity) /* Set your values */

    /* Query to update Stock */
    SET T1.Qty = T1.Qty - @Quantity
    FROM Stock T1
    INNER JOIN G_Invoice T2
    ON T1.SR_NO = T2.SR_NO
    where /* Set filters according to params */
	
END
GO

Finally, you can call the stored procedure from your access data layer making use of SQL Commands, Entity Framework, etc.