Abstract: Methods and apparatus for optimizing an abstract query are disclosed. Embodiments of the present invention allow an abstract database to optimize an abstract query composed from a set of logical fields. Each logical field includes a field name and an access method used to map the logical field to an underlying physical representation of the data. After a user composes an abstract query and submits it for execution, a runtime component and optimization component may be configured to resolve the abstract query to a physical query of the underlying physical data source using an access method associated with each logical field. In addition, as the runtime component builds a query consistent with the schema of the underlying database, an optimizing component may modify the query using any suitable optimization techniques.

Abstract: Methods, systems and articles of manufacture are provided for migrating entity relationship data residing in an object oriented program environment to a relational database schema. Further, functionality is provided to facilitate more efficient searching and reconstruction of the entity relationship data in the relational database.

Abstract: Statistics for a pattern matching predicate are generated using stored character statistics. A first structure stores, for each of a plurality of character positions, frequently occurring characters in that character position, and a count of the number of occurrences of that character. A second structure stores frequently occurring characters that are subsequent to the frequently occurring characters stored in the first structure, and a probability of occurrence of each frequently occurring subsequent character. To form an estimate of the number of tuples matching a pattern matching predicate, statistics are retrieved for the matching characters in each matching position in the predicate, and then combined to produce the estimate. In the event a statistic is not stored for a desired character, the available statistics are used to make an estimate by accumulating statistics for other characters, and then calculating average frequency of occurrence of characters that do not have stored statistics.