It should work but it doesn't.
I have referred others but couldn't find the reason.
OracleCommand cmd = con.CreateCommand();
var query = $@"UPDATE Customer SET ContactName = :ct WHERE CustomerID = :id";
cmd.CommandText = query;
cmd.Parameters.Clear();
cmd.Parameters.Add(new OracleParameter(":id", OracleDbType.Varchar2, "bbb1", System.Data.ParameterDirection.Input));
cmd.Parameters.Add(new OracleParameter(":ct", OracleDbType.Varchar2, "Joon", System.Data.ParameterDirection.Input));
var rst = cmd.ExecuteNonQuery();
Thanks in advance.
Joon