1. A method of creating a logical index on a partitioned table, the method comprising: computing each row value pID of a partition identifier column of the logical index using a partition function pf (Key) where each row value pID of the partition identifier column equals pf(Key) and where Key is a key value of a row corresponding to the row value pID in the logical index, the partition function being an order-preserving partition function where pf(input 1 )>=pf(input 2 ) when input 1 >input 2 where input 1 and input 2 are key values; appending an index key column from a pre-existing index on the partitioned table to the logical index, wherein the logical index includes each row of the pre-existing index, and wherein each corresponding row in the partition identifier column of the logical index includes a partition identifier equal to a return value from pf(Col) where pf is the partition function and Col is a value from an index column at the each row; and wherein the method performed by a computing device.