Fecha de publicación: -- Fuente: WIPO "tomato" Methods and systems for constraint-based selection of discrete units from external data systems. Data associated with ingredients of a cooking recipe is obtained. Candidate product records are retrieved from external systems. Each candidate product record corresponds to a product available from the external systems and specifies a unit quantity of a respective ingredient provided by a unit of the product and at least one attribute associated with the product. One or more candidate product records are identified based on the at least one attribute and constraints including a quantity constraint in which unit quantities specified by the candidate product records satisfy a quantity associated with the ingredients, and a unit-based constraint corresponding to fixed unit quantities of the products. A machine-readable data structure identifying the one or more candidate product records is generated and caused to be stored and made accessible to at least one client device.