Abstract: A system, method and program extender for enforcing the uniqueness of temporal data in an object/relational database management system is provided. There is a combination of user-defined functions, triggers and specified conditions to determine if attempts to insert new data or update existing data in a data object in which temporal integrity is a consideration are valid. Barriers exist to protect against inserts or updates that would violate the temporal integrity of the existing data. Also included are ways for a user to modify the behavior of the system or method to override triggers for cases in which temporal integrity is not desired.

Abstract: A method, apparatus and article of manufacture is provided for mapping persistent data objects residing in multiple data sources into a single, reusable software component accessible to an object-oriented programming language application performed by the computer, for multi-database access to data that may be physically distributed and stored in disparate DBMSs, each stored in an electronic storage device coupled to the computer. The method has steps for identifying data objects in multiple data sources, employing a multi-database software facility for connecting to the data sources containing the data objects, and registering the data objects with the multi-database software facility, creating a single virtual data object consolidating multiple attributes from the registered data objects, and establishing a connection to the multi-database software facility for referencing the virtual data object as though it was a single real data object.

Abstract: A method executed by a data processor for scanning a reverse range. The scan is conducted in an index for a table having an upper end and a lower end. The reverse range has a start key value for defining the reverse range, and the index has a set of keys representing a set of records and record attributes in the table. Each key in the set of keys has a RID designating a record in the table and a key value corresponding to an attribute of the record in the table. The method includes the steps of searching the index for a start key, selecting an upper bound of the reverse range, and, if the upper bound is the first key in the index, indicating that the index does not contain any key value within the reverse range, or, if the upper bound is not the first key in the index, then fetching each key below the upper bound in the index.

Abstract: A system, a program storage device and a software method, useable in a computer database system with a display device, is provided for displaying and selecting table joins. The method is capable of assisting in a user's selection of a table join by displaying all user-selected database tables in a join overview diagram and automatically inferring and displaying in a join grid each join grid row having a potential valid table join for a pair of user-selected database tables. The method accepts the user's selection of a join grid row from the join grid, and, in response, places a join indicator in the join overview diagram between icons representing the pair of user-selected database tables from the user-selected join grid row. The user's join grid row selection is performed with a single operation.

Abstract: An optimization technique for SQL queries, a program storage device storing the optimization program, and an apparatus for optimizing a query is provided. A query is analyzed to determine whether it includes the WHERE clause which contains an “EXISTS” subquery and a “NOT EXISTS” subquery, or EXISTS-equivalent subqueries, in Boolean factor. If so, the subsumption test is performed on two subqueries. Then, the compensation predicate is applied to one of them, to perform the QGM transformation of the query. One subquery block is stacked on top of the other subquery block, in order to eliminate one subquery. This procedure allows the transformed query to perform more efficiently than the original query while providing same results. The query is then executed in the computer to efficiently retrieve data from the relational database.

Abstract: A method, apparatus, and article of manufacture for a computer-implemented technique for query optimization using a multi-layered object cache. An object-oriented query is executed to retrieve data from a database. The database is stored on a data storage device connected to a computer and queries are run against lower cache layers which have better performance characteristics than the external or upper layers. The multi-layered cache has an application objects (AOs) cache and a data access objects (DAOs) cache, and the application objects include methods deriving data from DAOs. The method includes a step of rewriting the query into a query directed against the DAOs cache, applying a pushdown transformation algorithm to the rewritten query directed against the DAOs cache, and executing the transformed query against the DAOs cache. The method also allows optimizing queries with path expressions by transforming path expression into joins.