1. A computer-implemented method of processing a query for accessing data within one or more database objects, wherein an element of a database object is stored among a plurality of different storage regions with each storage region being associated with first and second range values indicating a value range for element values within that storage region, the computer-implemented method comprising: determining an effectiveness value representing a degree of overlap between the storage regions of each database object element by examining the first and second range values for the storage regions of that database object element; determining a selectivity model for the storage regions for each database object element of the query utilizing the effectiveness value; determining a query plan for the query based on the selectivity model for one or more corresponding database object elements; and executing the query plan to access data from the database objects for the query.