What is the Numeric and Boolean type in npgsql?

I am using postgreSQL database. I need to add "Numeric" and "Boolean" parametres with SQL query. What do I have to write where I wrote in the code "XXX" Here is the source code:

NpgsqlCommand TupCmd = new NpgsqlCommand("UPDATE istabu_tipi SET cena=@cena,istabas_tipa_apraksts=@apr,smeketaju=@smek WHERE id_istabas_tips=@id", con);
        TupCmd.Parameters.Add(new NpgsqlParameter("@cena", NpgsqlTypes.NpgsqlDbType.Numeric, XXX, "cena"));
        TupCmd.Parameters.Add(new NpgsqlParameter("@apr", NpgsqlTypes.NpgsqlDbType.Varchar, 255, "istabas_tipa_a开发者_高级运维praksts"));
        TupCmd.Parameters.Add(new NpgsqlParameter("@smek", NpgsqlTypes.NpgsqlDbType.Boolean, XXX, "smeketaju"));
        TupCmd.Parameters.Add(new NpgsqlParameter("@id", NpgsqlTypes.NpgsqlDbType.Integer, sizeof(int), "id_istabas_tips"));

For boolean you can put the size of 1. For numeric you can use a value of 4.

Npgsql doesn't make use of this size for numeric types or boolean. It is mainly used for char and varchar datatypes.

I hope it helps.