Patent ID: 6490578
Filing Date: 2002-12-03
Classification: G06F,Y10S

Abstract:
In a database system for representing information in database tables and for retrieving information from database tables in response to database queries, each database table comprising data records storing information categorized into one or more database columns, each database column storing information as an attribute having a particular data type, a method for creating a specialized date index for a particular database column storing date information, the method comprising:creating a plurality of year bitmaps, wherein each year bitmap stores a successively smaller subrange of year values present in the particular database column; creating a plurality of month bitmaps, wherein each month bitmap stores a successively smaller subrange of month values present in the particular database column; creating a plurality of day bitmaps, wherein each day bitmap stores a successively smaller subrange of day values present in the particular database column; creating an existence bitmap, for indicating whether a particular record exists for a given record identifier (record ID); and wherein upon receipt of a database query including date criteria that specifies selection of data records based at least in part on date values from said particular database column, the database system may determine a result set satisfying said date criteria by performing set operations on said bitmaps.