Techniques for efficient integration of text searching with queries over XML data

A machine-implemented method, comprising the steps of:

• storing, within one or more structures of a database, data for an XML document;
• receiving a database command with an embedded XML query expression, wherein the embedded XML query expression specifies (a) a path that identifies one or more locations within the structure of the XML document, and (b) search criteria for filtering the one or more locations based on content contained within the one or more locations;
• upon determination that a set of conditions is satisfied, rewriting the database command to additionally recite a database function, wherein, upon executing the database command, the database function acts as a primary filter;
• executing a first portion of the database command to retrieve, from the one or more structures, a first data set, wherein the first portion includes the database function;
• and
• executing a second portion of the database command, against the first data set, to identify data within the first data set that satisfies the search criteria specified in the embedded XML query expression, wherein the second portion includes the embedded XML query expression.

A machine-readable medium carrying one or more sequences of instructions, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

• storing, within one or more structures of a database, data for an XML document;
• receiving a database command with an embedded XML query expression, wherein the embedded XML query expression specifies (a) a path that identifies one or more locations within the structure of the XML document, and (b) text search criteria for filtering the one or more locations based on content contained within the one or more locations;
• determining whether an index should be used as a primary filter;
• upon determination that a set of conditions is satisfied, transforming, within the database command, the embedded XML query expression into a rewritten expression that includes a text function, wherein the text function specifies the path and the text search criteria, and wherein the text function includes a reference to the index if it was determined that the index should be used;
• and
• executing the database command to retrieve data from the one or more structures based on the path and the text search criteria specified in the rewritten expression.

A machine-readable medium carrying one or more sequences of instructions, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

• storing, within one or more structures of a database, data for an XML document;
• receiving a database command with an embedded XML query expression, wherein the embedded XML query expression specifies (a) a path that identifies one or more locations within the structure of the XML document, and (b) search criteria for filtering the one or more locations based on content contained within the one or more locations;
• upon determination that a set of conditions is satisfied, rewriting the database command to additionally recite a database function, wherein, upon executing the database command, the database function acts as a primary filter;
• executing a first portion of the database command to retrieve, from the one or more structures, a first data set, wherein the first portion includes the database function;
• and
• executing a second portion of the database command, against the first data set, to identify data within the first data set that satisfies the search criteria specified in the embedded XML query expression, wherein the second portion includes the embedded XML query expression.