摘要:
Techniques are provided for mapping XML data and metadata from data in relational databases. According to certain embodiments of the invention, a mechanism is provided to allow the user to use a database query to retrieve data form a relational database in the form of XML documents by canonically mapping object relational data to XML data and canonically mapping object relational schemas to XML-Schemas. The mechanism causes the generation of XML-schema information for the XML documents.
摘要:
In an automated fashion, a collection of XML documents are traversed and statistical data is generated describing hierarchical relationships of the elements, the elements data types and values. Based the analysis, an XML schema is derived such that the collection of XML documents conforms to the schema to a certain degree.
摘要:
XML Schema design often involves repeating work already done by others. Schema designers benefit from a system that helps designers choose from a set of candidate XML tags already in use by others. Mechanisms are described for providing decision support in the selection of candidate XML tags based on tags that are in use within a collection of XML documents. The approaches presented include a static analysis of tags which reflects the use of such tags in documents considered to be of high quality. A real-time analysis of tags considers the shared context of candidate XML tags with the set of tags already selected for use in the schema under design. Measure values resulting from the static analysis and/or the real-time analysis are used to derive an overall ranking measure for each candidate tag, and the candidate tags may be displayed in rank order of their measure values.
摘要:
Disclosed is a method and mechanism for processing expressions and operator trees. An approach is particularly useful to optimize processing of XML statements with respect to SQL operators. A top-down processing approach can be taken to directly output data from operators to a data stream. In addition, multiple processing approaches can be taken within a single expression tree, with some operators processed using the top-down approach and other operators processed with the bottom-up approach. Even data that can not be streamed is copied fewer times using this approach, intermediate values from bottom-up processing may still be streamed if it is used by an operator that is eligible for top-down processing.
摘要:
The techniques presented herein are directed towards providing a user-directed keyword-based search on a large collection of XML documents, and displaying a summary of results to the user. Prior to receiving search requests from a user, an offline analysis of a large collection of XML documents is performed to construct an inverted index of keywords. For each keyword, the index stores a set of location indicators that identify all the instances of the keyword found in the collection of documents. A location indicator may comprise a document identifier, an indication of the position of the node in the hierarchy of nodes within the XML document containing the keyword, and an indication of the pathname of the node containing the keyword. Once the index is constructed, keyword searching can be done efficiently by a keyword lookup in the index. Various display strategies enable the user to see the specific portion of a large XML document containing the keyword and/or path frequency information allowing the user to easily refine the search to specific paths within the collection of documents.
摘要:
In an automated fashion, a collection of XML documents are traversed and statistical data is generated describing hierarchical relationships of the elements, the elements data types and values. Based the analysis, an XML schema is derived such that the collection of XML documents conforms to the schema to a certain degree.
摘要:
A method and apparatus for rewriting a database command containing an embedded XML expression such that the rewritten database command recites a text function, in lieu of the embedded XML expression, is provided. Advantageously, a DBMS may take advantage of the efficiencies in storing XML data within the database, while avoiding the generation of unnecessary XML elements in processing the query when the XML elements contribute nothing to the outcome of the query. Cost-base or rule-based analysis may be performed to determine how to rewrite a received database command. The database server may functionally evaluate the text function or may use an index defined on a column of the database. The text function may function as a primary filter or may reference a column upon which an index is defined, wherein the index operates at the same or higher level than a column being referenced in the embedded XML expression.
摘要:
Access control rewrites generate rewritten queries that may be executed more efficiently using index evaluation to determine which rows satisfy one or more access control conditions.
摘要:
Efficiently replicating XML data among databases includes techniques for (a) replicating XML data involved with an insert operation; (b) replicating XML data involved with an update operation; (c) leveraging existing relational replication techniques for XML data stored in shredded form using object-relational constructs; and (d) replicating XQuery Data Model sequences. Each technique reduces the amount of information that would otherwise need to be transmitted over a network for XML data replication purposes.
摘要:
Techniques are provided for mapping XML data and metadata from data in relational databases. According to certain embodiments of the invention, a mechanism is provided to allow the user to use a database query to retrieve data form a relational database in the form of XML documents by canonically mapping object relational data to XML data and canonically mapping object relational schemas to XML-Schemas. The mechanism causes the generation of XML-schema information for the XML documents.