Oracle International Corporation

Anguel Novoselsky

Zhen Hua Liu

Thomas Baby

Sukhendu Chakraborty

Junyan Ding

Muralidhar Krishnaprasad

Vikas Arora

Kongyi Zhou

K Karun

Jinyu Wang

Tim Wing Yu

Meghna Mehta

Yuhuan (Bill) Han

A method and apparatus are provided for building and using a persistent XML tree index for navigating an XML document. The XML tree index is stored separately from the XML document content, and thus is able to optimize performance through the use of fixed-sized index entries. The XML document hierarchy need not be constructed in volatile memory, so creating and using the XML tree index scales even for large documents. To evaluate a path expression including descendent or ancestral syntax, navigation links can be read from persistent storage and used directly to find the nodes specified in the path expression. The use of an abstract navigational interface allows applications to be written that are independent of the storage implementation of the index and the content. Thus, the XML tree index can index documents stored at least in a database, a persistent file system, or as a sequence of in memory.

Efficient XML tree indexing structure over XML content

A method, computing device, and a non-transitory computer-readable medium are provided for performing a context-aware search by finding a set of nodes that are mapped to a given text or other value and, for each node in the set of nodes, performing a reverse path lookup to determine whether the node satisfies a given context. The query processor performs the reverse path lookup for a node by traversing up a node tree away from the node, using a stored mapping from the node to a parent of the node. Using mappings from nodes to parent nodes, the node tree is traversed backwards from the node up to distant ancestor nodes through parent nodes. An optimizer instructs the query processor to perform a value-based portion of the search before a path-based portion of the search based on value distribution statistics and path distribution statistics.

Searching backward to speed up query

A method, computing device, and a non-transitory computer-readable medium is provided for facilitating a context-aware search on documents stored in an unstructured database column. The database server determines whether a document stored in an unstructured database object is marked up according to a recognized markup language. Documents that conform to the markup language are indexed with value-to-node mappings and node-to-physical-location mappings to provide a context-aware search of marked up nodes within the documents. Documents that do not conform to the markup language are indexed with value-to-document mappings to provide a full-text search of the documents. The database server evaluates a context-aware search against documents that conform to the markup language within the unstructured column without requiring the user identify the documents as XML documents and store the documents in an XMLType structured column.

Providing context aware search adaptively

A system which combines sequential and iterative source code is provided. The system decides which type of processing would be most suitable for all portions of the source code, regardless of type. The system can adjust that decision based on the specific nature of the constructs within the source code, and can also adjust that decision based on the platform upon which the resulting executable program will run.

Efficient compilation and execution of imperative-query languages

Techniques are provided for efficiently evaluating XML queries that conform to an extension of an XML language (e.g., XQuery or XPath). The extension allows XML queries to have full-text search capabilities. Such an XML query is compiled to generate a tree of nodes that correspond to one or more conditions in the full-text portion of the query. In one technique, the amount of memory for the execution state of the tree is determined at compile time and allocated only once throughout execution of the query. In another technique, to ensure at most a single scan of a document, all the words or phrases in the full-text portion of an XML query are located before any of the other conditions in the full-text portion are evaluated. In another technique, the elements of the full-text portion of an XML query are analyzed to determine, based at least in part on cost, which evaluation strategy, of a plurality of evaluation strategies, should be employed.

Efficient evaluation of XQuery and XPath full text extension

Transformation of a set of XML documents via an XSLT stylesheet is made more efficient by rewriting the stylesheet at compile-time, based on the structural description of the set of XML documents, into an optimized stylesheet containing fewer dynamic template-matching calls than the original stylesheet. This rewritten stylesheet can be further rewritten into a set of XQuery expressions. At compile-time, the particular transformation templates that are appropriate for transforming the particular nodes contained in the set of XML documents are determined, and XSLT calls to the templates are converted to calls to corresponding XQuery user-defined functions. Determination of the appropriate transformation templates may be based on the structural description of the input set of XML documents, such as an XML Schema or Document Type Definition. The data from each template is translated into corresponding XQuery constructors, instructions from the template are translated into XQuery expressions, and the XQuery functions are inlined if possible.

Optimizing XSLT based on input XML document structure description and translating XSLT into equivalent XQuery expressions

A method and apparatus is provided for partial evaluation of XML queries for program analysis. An executable version of a first body of instructions that conforms to an XML computer language, such as XSLT, is generated. The executable version may include trace instructions for collecting information about executing the executable version against representative data, such as an XML schema document. This execution causes the generation of an execution graph, which may be optimized by the collected information. Based on the execution graph, a second body of instructions is generated that conforms to a different computer language, such as XQuery. Subsequently, the second body of instructions may be applied against XML documents that conform to the same schema as the representative data. By generating the second body of instructions before source XML documents are received, several optimizations may be made that greatly decrease the time for querying and/or transforming XML documents.

Partial evaluation of XML queries for program analysis

Techniques for implementing a schema-aware mid-tier binary XML are provided. Token vocabularies are stored in a repository that is accessible to mid-tier applications from separate database systems. The token vocabularies are thus shared among the mid-tier applications of each database system. The repository may be part of a file system or database that is separate from any of the database systems, or the repository may be part of one of the database systems.

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Foster City, CA, United States of America

Anguel Novoselsky