check if value already exist

Question

i have a table stock with column stock_idstock_code stock_desceription etc stock_id is the primary key while i have stock_code is indexes/key i want stock_code to be unique i every rowam able to do so and also am able to check whether stock_code exist before i insertnow my question is how can i be able to check for dublicate before i update below are my code that check before i insert tStock = svcClient.GetLocationStocksByScanCode(MainConn cbolocation.SelectedValue TxtScancode.Text).FirstOrDefault If Not IsNothing(tStock) Then MessageBox.Show(Item already exist in the location! Softbit Tech) Return End If now what can i do to check before i update

Ramesh Barik · Answer

Before inserting records to the DB check whether this record is exsts or not. Ex: IF not Exists(select 1 from yourtableName where stock_code =@stock_code ) begin // Write your insert statemnt end else begin // You can write your update code or else you can select a status as exists end

Ramesh Barik · Answer

Dear Carlos kambui No need of exist check at the time of update. Just write the update statement with the conditions EX: Update table set YourCoulm=YourValue where YourOtherColumn=YourCondiion.

Carlos kambui · Answer

am able to check if it exist when am inserting problem is when am updating it must exist for it to be updated how can i check if it exist and also update

Ranjeet Patra · Answer

Query on stock table with the stock_code before you insert/update...If you are getting any record with that stock_code that means you have data with the stock_code...and they you can simple show your message like: MessageBox.Show(Item already exist in the location! Softbit Tech)

Jitendra Shekhawat · Answer

con.Open(); cmd = new SqlCommand(SELECT COUNT(*) FROM database WHERE [Name] = @Name con); cmd.Parameters.Clear(); cmd.Parameters.AddWithValue(@Name txtName.Text); int numRecords = (int)cmd.ExecuteScalar(); con.Close();