| 摘要 |
The present invention involves a computer for implementing a complex database management system. A processor has at least one complex database with extraction software. The database extraction software is capable of creating a perspective based data model from a user selected data table of the database. A query is specified by user selection of attributes from a data table of the database. A perspective based data model is created from the user selected data base table of the database and related tables. The extraction software creates a query structure defining a plurality of paths providing a selected portion of the information in the database, which is presented to the user based on the perspective based data model. The query structure defines a plurality of paths and having a plurality of nodes, each of the nodes having a corresponding operand. A downward evaluation of the query structure is performed, proceeding from a starting object down downwardly through the paths. An upward evaluation of the query structure is performed, proceeding upwardly from the bottom of each path. The operands are resolved according to predetermined rules so that the number of evaluations of the nodes is less than the number of instances of each operand in the query structure.
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