In a method for storing data in a relational database system using a processor, a collection of values is assigned to a structure dictionary, wherein each of the values represents the value of a row for an attribute and has a unique ordinal number within the collection, and wherein 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, and predetermined information about structures relevant to data content that is stored in the system. For each structure in the structure dictionary, a structure match list is formed from ordinal numbers of values matching the structure, and a structure sub-collection from values matching the structure, using the processor. An outlier match list is formed from ordinal numbers of values that are not null and do not match any structure in the structure dictionary, and an outlier sub-collection from values that are not null and do not match any structure in the structure dictionary. The collection of values is stored in the relational database in a form of structure match lists, structure sub-collections, outlier match list and outlier sub-collection.