public void AddCompanies(IEnumerable <Company> companies) { string sql = "INSERT INTO gcp (gcp_cd, gln_nm, gln_addr_02, gln_addr_03, gln_addr_04, gln_addr_postalcode, gln_addr_city, contact_tel, contact_mail) " + "VALUES (@gcp_cd, @gln_nm, @gln_addr_02, @gln_addr_03, @gln_addr_04, @gln_addr_postalcode, @gln_addr_city, @contact_tel, @contact_mail)"; var parametersList = new List <NpgsqlParameter[]>(); foreach (var company in companies) { var companyDataModel = new CompanyDataModel(company); parametersList.Add(companyDataModel.GetNpgsqlParameters().ToArray()); } RunTransaction(sql, parametersList); }