Patent ID: 7890453

Claim:
A method of representing and providing access to old and new versions of a hierarchical set of engineering project documents stored in a hierarchy of data arrays, the data arrays corresponding to the documents in the hierarchy of documents, the method including: representing one or more of old versions of the hierarchical set of documents stored in computer readable memory as packages of data entry rows in at least two data arrays in a hierarchy, wherein a new version of the documents is based on an addition to or change in an old version of the documents; wherein each data array includes a plurality of data entry rows, each data entry row includes a plurality of fields, and the plurality of fields includes at least one version field that indicates one or more versions of the documents to which the data entry row belongs; wherein the plurality of fields further includes at least one characteristic field of document data; initializing a package of data entry rows representing one of the old versions of the documents to represent a new version of the documents by appending a new version indicator to the data entry rows representing the old version; and responding to queries for all or part of a particular version of the hierarchical set of documents using a processor to filter the data entry rows from the at least two data arrays based on the version field and to select particular data entry rows that represent the particular version.