1. A sequence online analytical processing (S-OLAP) system for analysing an event database storing events, each event consisting of at least one dimension and measure, the system comprising: a sequence cuboid (S-cuboid) builder to build an S-cuboid, the S-cuboid defining a logical view of sequences of the events at a predetermined degree of summarization; wherein the S-cuboid built by the S-cuboid builder is specified by: a WHERE clause to select events of interest from the events stored in the database; a CLUSTER BY clause to specify those of the selected events of interest that are elements of respective sequences to be clustered together, thereby forming one or more clusters of events; a SEQUENCE BY clause to form sequences from respective clusters of events; a SEQUENCE GROUP BY clause to group those of the sequences whose events share a common dimension value, thereby forming one or more sequence groups; a CUBOID BY clause to specify the logical view of the sequences of the events, the CUBOID BY clause comprising (i) a pattern template to define a format of substring/subsequence patterns to be matched against the sequences of events, (ii) a cell restriction to define how a response and content of the sequence of events should be assigned to a cell of the S-cuboid when a sequence of events contains multiple occurrences of a cell's pattern, and (iii) a matching predicate to select sequences of interest; and at least one aggregation function to be applied to sequences of the events in each cell of the S-cuboid.