Question

Im trying to perform a parameterized query in SQLite from C#, and the method im using is along the lines of creating a static command with

        SQLiteCommand cmd = new SQLiteCommand(
        "SELECT [ID]" +
            ",[email]" +
            ",[serializedata]" +
            ",[restrictions]" +
        " FROM " + UserTable +
        " WHERE @search = @searchparam", SQLConnection);

        cmd.Parameters.Add(new SQLiteParameter("@searchparam"));
        cmd.Parameters.Add(new SQLiteParameter("@search"));

and calling it like this:

        Command.Parameters["@searchparam"].Value = searchdata;
        Command.Parameters["@search"].Value = search;
        SQLiteDataAdapter slda = new SQLiteDataAdapter(UserSelectUsernameCommand);
        DataSet ds = new DataSet();
        slda.Fill(ds);
        User[] array = new User[ds.Tables[0].Rows.Count];
        int index = 0;
        foreach (DataRow row in ds.Tables[0].Rows)
        {
            array[index] = new User(this, row);
            index++;
        }
        return array;

but im getting an error along the line of ” ‘@search’ is not a correct column name ” or something like that. if i use a constant column name, and only use the data for parameters it works, but i dont want to create 10 different commands for when i need to search by different column names.

What is the issue here?

Answer 1

Generally things like column names (or table names) can not be parameterised – and the fact that there are different indices means that it will have to be a different plan internally. So you will have to use concatenation – but be careful to white-list the known column names to prevent sql injection:

    SQLiteCommand cmd = new SQLiteCommand(@"
    SELECT [ID],[email],[serializedata],[restrictions]
    FROM " + whiteListedUserTable + @"
    WHERE [" + whiteListedColumnName + @"] = @searchparam", SQLConnection);

    cmd.Parameters.Add(new SQLiteParameter("@searchparam"));
    ...
    Command.Parameters["@searchparam"].Value = searchdata;