1. A method of using an index shared between a plurality of tables to access a data sharing space (DSS) storing a set of rows from a base table having a plurality of rows with stored data, the method comprising: identifying, in response to a first query for a first table of the plurality of tables, first data values of the index; retrieving, using index elements corresponding to the first data values, a first subset of the set of rows from the DSS; identifying, in response to a second query for a second table of the plurality of tables, second data values and at least some of the first data values of the index; retrieving, using the index elements corresponding to the second data values and the at least some of the first data values, a second subset of the set of rows from the DSS; and applying the query to the subset of the set of rows.