Patent ID: 7103596

Claim:
A data sort method of rearranging records according to a specified sort key item in an ascending/descending order, comprising: an automaton generating step of generating, in a main memory, an automaton which receives a character string of a sort key item of each record read successively from outside, and which is a set of state transition tables with a hierarchical tree structure whose hierarchical depth is equal to a maximum number of characters of a character string of a sort key item of each record, and whose transition table corresponds to each character of a character string of the sort key item of each record, and also whose state transition table contains links to next stage state transition tables each of which corresponds to a next character of a character string of the sort key item of each record in an ascending/descending order according to each of the next characters, and which associates a record identifier of each record with a final state transition table corresponding to the final character of a character string of the sort key item of the record; and an order value tuple generating step of generating an order value tuple which is a set of a record identifier of the record and an order value which is obtained by arranging the records in an ascending/descending order by scanning the automaton in order of contained links in the state transition tables giving priority to the depth direction of the hierarchy of the state transition tables.