Abstract: In a method for storing data in a relational database system using a processor, a collection of values is assigned to a structure dictionary, each of the values represents the value of a row for an attribute and has a unique ordinal number within the collection. and the structure dictionary contains structures defined based on at least one of interaction with a user of the system via an interface, automatic detection of structures occurring in data, automatic detection of frequencies of values occurring in data, analysis of a history of queries, and predetermined information about structures relevant to data content that is stored in the system. For each structure, forming a structure match list from ordinal numbers of values matching the structure, and a structure sub-collection from values matching the structure, using the processor.