Tradeoff Based search

While SQL search offers great flexibility to search the data, it still operates like a computer does: by constraints. In SQL, constraints are used to eliminate the data, while tradeoff based search uses a more "human" metaphor. For example if you are searching for a car in a dataset, your SQL statement looks like: select car from dataset where price < $30,000, and Consumption > 30MPG, and Color = 'RED'. While a tradeoff type query would look like "I like the red car, but I will settle for the blue if it is $2,000 cheaper".