Abstract: A method and computer system for implementing concurrent edits of a database record by a plurality of users is provided. The preferred embodiment allocates a fixed amount of storage space in the computer system's main memory for each of the plurality of users. The fixed amount of storage space is for storing versions of the record created as a result of the user modifying the record. In response to an access request for the record by one of the plurality of users, the preferred embodiment determines whether the user should be given access to the record itself or to one of the versions of the record, if any exist. When the user modifies the record to create a version of the record, the preferred embodiment stores the version of the record within the fixed amount of storage space allocated to the user.

Abstract: A computer method and storage structure for storing and accessing multidimensional data is provided. A tree manager provided by the present invention stores data such as pointers, variable length data records, other B-trees, and directories, in a Multidimensional B-tree (MDB-tree). An MDB-tree has an imbedded "parent-child" structure which allows subtrees to be stored within nodes. The subtrees contain subnodes, which, in turn, may contain subtrees. The nodes are indexed by a primary key value while the subnodes in a subtree are indexed by secondary key values. Nodes of a MDB-tree contain a key value table, a subnode table, and a data area. When the tree manager attempts to store a unit of data on a page and the unit of data is too large for the page, the tree manager attempts to split a node currently stored on the page (or the unit of data being inserted) into a subnode and a subtree. The subtree is then stored on a new page.

Abstract: A method and system for displaying results of multiple level aggregation queries and providing hierarchical table sets in response to multiple level aggregation queries. In a preferred embodiment, a database engine program receives multiple-level aggregation queries from a database front-end program. A multiple level aggregation query defines two or more data aggregation levels. In response to a multiple-level aggregation query, the engine creates a hierarchical table set, which contains a separate table for each level of aggregation specified by the multiple-level aggregation query. Each table in the hierarchical table set contains the aggregation information for one level of the multiple-level aggregation query. In a preferred embodiment, the front-end uses the tables in the hierarchical table set to generate a hierarchical window display that the user can view.

Abstract: A method and system for supporting scrollable, updatable database queries is provided. In a preferred embodiment, a database engine receives a query request specifying the retrieval of data from a source table stored by the engine. The engine then generates a query table that contains references to rows of a source table that satisfy the query request. The engine then receives one or more retrieve requests requesting that data specified by the query be provided by the engine. For each retrieval request, the engine retrieves data from the source table using one Or more references from the query table.

Abstract: A method and computer system for implementing concurrent edits of a database record by a plurality of users is provided. The preferred embodiment allocates a fixed mount of storage space in the computer system's main memory for each of the plurality of users. The fixed amount of storage space is for storing versions of the record created as a result of the user modifying the record. In response to an access request for the record by one of the plurality of users, the preferred embodiment determines whether the user should be given access to the record itself or to one of the versions of the record, if any exist. When the user modifies the record to create a version of the record, the preferred embodiment stores the version of the record within the fixed amount of storage space allocated to the user.