check if value already exist

Carlos kambui

9y1.1kSQL

i have a table stock with column stock_id,stock_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 row,am able to do so and also am able to check whether stock_code exist before i insert,now 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

5 Replies

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Ramesh Barik9y ago
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 kambui9y ago
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 Patra9y ago
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")
Ramesh Barik9y ago
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
Jitendra Shekhawat9y ago
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();