dao6

public class UserDao
{
    public User findById(int id)
    {
        var command = newDataSource().CreateCommand("SELECT * FROM TABLE WHERE ID = {id}");
        // execute command etc.
    }

    public User findByFirstName(string firstName)
    {
        var command = newDataSource().CreateCommand("SELECT * FROM TABLE WHERE ID = {firstName}");
        // execute command etc.
    }

    private NpgsqlDataSource newDataSource()
    {
        return NpgsqlDataSource.Create("Server=mydemoserver.postgres.database.azure.com;" +
           "Username=mylogin@mydemoserver;" +
           "Database=mypgsqldb;" +
           "Port=5432;" +
           "Password=<server_admin_password>");
    }
}