A searchable database comprising a multiplicity of tables including an attributes table and a values table for a multiplicity of target search items constructed and arranged so that selection of values for one or more target search item attributes yields an attribute-value construct specifying a particular one of said target search items and precluding an indeterminate search result. Such database may be employed in an online comparison shopping system comprising a database containing product information of multiple vendors, manufacturers and/or products and a user interface generating a virtual shopping cart, and constructed and arranged to enable a user to selectively aggregate an order in said virtual shopping cart, comprising products represented in said database, and means for electronically disaggregating said order to generate vendor-specific orders to respective vendors.