Patent ID: 7933910

Claim:
A retrieving apparatus for retrieving hierarchical structure data, the retrieving apparatus being implemented by a computer and comprising: an input means for inputting: parent-child relationship data defining hierarchical relationships between parent and child items, operation instruction data providing one or more instruction instructing at least one operation on the parent-child relationship data, and retrieval data defining a showing condition used for retrieving the parent-child relationship data; a data storage means for storing the parent-child relationship data inputted by the input means; a data updating means for updating the parent-child relationship data stored in the data storage means, in accordance with the operation instruction data inputted by the input means; and a retrieving output means for retrieving select said parent-child relationship data stored in the data storage means, in accordance with the showing condition defined by the retrieval data inputted by the input means; wherein the parent-child relationship data stored in the data storage means includes a data item concerned with an effective term defining a term for utilizing the data, and another data item concerned with a change term defining a changed term of the data where a data content is changed; the retrieval data inputted by the input means has the showing condition instructing retrieval of one data concerned with the effective term, and two dates concerned with the changed term; and the retrieving output means retrieves two sets of parent-child relationship data, where the two sets of parent-child relationship data relate to the one data and include a changed condition at the two dates with respect to each other, and outputs two opposing hierarchical graphical representations corresponding to the two sets of parent-child relationship data, respectively, where hierarchical elements common to both said two opposing hierarchical graphical representations are aligned with each other for intuitive visual comparison thereof.