Abstract: 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.

Abstract: Techniques for managing XML data in an SQL compliant DBMS include receiving an SQL statement. The SQL statement includes a particular operator that operates on a first instance of XML type that represents a first set of XML elements. During execution of the SQL statement, the particular operator is evaluated by generating an ordered collection of instances of XML type. Each different instance in the ordered collection is based on a different XML element from the first set; and there is an instance in the ordered collection for every XML element from either the first set or from the first set and its descendents. When descendents are included, each entry in the ordered collection indicates a level in the XML tree. In another aspect, an aggregate operator in the SQL statement operates on a collection of instances, with associated levels, to generate a single instance of XML type.

Abstract: To associate XML data objects (“child objects”), stored in rows of relational or object-relational tables, with the appropriate XML data objects (“parent objects”) from which the child objects descend, tables that contain child objects (“out-of-line” tables) are constructed with an additional column. In one embodiment, this column stores values that identify the root objects, in the appropriate table, from which the respective child objects descend. Hence, the root object from which any given object descends is traceable by following the respective value back to the corresponding root object. In one embodiment, this column stores values that identify the complete XML hierarchical path, through multiple tables, back to the root object from which the respective child objects descend. Consequently, XML query language queries against XML documents stored in such tables can be rewritten as SQL queries against the data in the tables, even in the presence of cyclic constructs.

Abstract: A database server that manages a database retrieves metadata that is stored, within the database, in association with a procedure that is stored in the database. Based on the metadata, a Web service definition is automatically constructed to describe the procedure as a Web service. The WSDL definition can be referenced to construct SOAP messages with the appropriate arguments and in the appropriate format which, when received, are converted to a suitable format for invoking execution of the procedure by the database server.

Abstract: An XQuery access API is described, for providing access to XML data from a data source, using the XQuery language. A requestor can request, from a server, performance of an operation on XML data, wherein request messages and response messages conform to the Simple Object Access Protocol (SOAP). Request and response messages can be transmitted using Hypertext Transfer Protocol (HTTP) or Hypertext Transfer Protocol over Secure Socket Layer (HTTPS). The format of the request and response messages is specified in a definition of a Web service, where the definition conforms to the Web Service Description Language (WSDL).

Abstract: Techniques for transferring a serialized image of data for an XML construct includes selecting a first format from multiple different XML serialization formats that represent, in a database system, data for XML constructs as a series of data units, such as a series of bytes representing characters, or a series of bits, bytes or octets representing binary values. A message is generated that includes a payload and a payload type field. The payload includes particular serialized data that represents particular data for a particular XML construct in the first format. The type field includes data that indicates the first format. The message is sent from a sending component of the database system to a different receiving component of the database system. These techniques allow the format selection to be based on characteristics of the sending or receiving components to make better use of the resources available to the two components.

Abstract: A universal format is used to create a type representation of XMLType instances that are generated in various ways from various sources. An XMLType Type Tree is represented as a hierarchy of nodes, including leaf item node, composite item node, operator node, aggregate node, referred to herein as an XMLType Type Tree. An XMLType Type Tree serves as a digest of the type structure of XMLType, no matter the source of the XMLType instance or its manner of its generation and it creates one uniform abstraction of the type structure of XMLType for the data-typing analysis of XPath and XQuery during query compile time.

Abstract: Techniques are provided for processing a query, including receiving the query, where the query specifies certain operations to be performed, including (a) a first set of one or more operations that are to be performed on a markup language data source and (b) a second set of one or more operations that are to be performed on a second data source. Then it is determined that a first server that manages the markup language data source is capable of performing the first set of operations. A request is sent to the first server to perform the first set of operations. A response is received, where the response contains results of performing the first set of operations on the markup language data source. Finally, results are generated for the query based at least in part on the results of performing the first set of operations.

Abstract: Object-relational database systems process XML values in a way that preserves node identities of nodes in the XML values and perform node-id based operations more efficiently or even in circumstances where such operations were not performed. An object-relational database system represents an XML value as a serialized stream of bytes, herein referred to as a serialized image. A serialized image may represent an XML value of the XMLType that is stored and/or generated by an object-relational database system. The serialized image contains one or more node identifiers that identify nodes within the XML value. The serialized image may also contain a pointer to an in-memory representation of the XML value, allowing the in-memory representation to be accessed via the pointer without having re-create the in-memory representation.

Abstract: Techniques are provided for processing a query including receiving the query, where the query specifies certain operations; determining that the query includes a first portion in a first query language and a second portion in a second query language; generating a first in-memory representation for the first portion; generating a second in-memory representation for the second portion; generating a third in-memory representation of the query based on the first in-memory representation and the second in-memory representation; and performing the certain operations based on the third in-memory representation.

Abstract: Techniques for managing XML data associated with multiple execution units ensure that execution units are able to use XML data coming from other execution units. Such techniques are applicable when, but for the technique, an XML type value is produced in a particular form by one execution unit and is supposed to be consumed by another execution unit that is unable to process data in the particular form, and involves detecting that the foregoing situation exists and annotating information sent to an XML producer execution unit to cause the XML type value to be transformed into a canonical form that can be shared by all relevant execution units.

Abstract: Techniques are described for executing queries that have XPath sections that specify unmappable paths. The techniques involve splitting the unmappable paths into (1) a mappable path fragment, and (2) an unmappable path fragment. After an unmappable path has been split into a mappable path fragment and an unmappable path fragment, the XPath section is replaced with a replacement XPath section. The replacement XPath section specifies two operations: a “mappable operation” that is based on the mappable path fragment, and an “unmappable operation” that is based on the unmappable path fragment. The portion of the replacement XPath section that specifies the mappable operation is rewritten to access underlying relational structures. Consequently, when the rewritten query is executed, a smaller amount of XML data needs to be materialized to evaluate the unmappable path fragment than would otherwise have been required to evaluate the original unmappable path.

Abstract: 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.

Abstract: Techniques are provided for changing data for an XML construct in an SQL/XML compliant database management system (DBMS). The DBMS allows instances of XML type to represent XML constructs, such as XML documents, XML elements, XML attributes, and fragments of XML documents. An SQL statement is received that includes an XML operator that operates on a particular component in an instance of XML type. During execution of the SQL statement, the XML operator is evaluated by modifying content for the component without modifying the entire instance. For example, an XML delete operator deletes the particular component from the instance. Other XML operators include an insert operator, an insert-before operator, an append-child operator, and an update operator. During execution, these operators may be rewritten to operate on existing SQL constructs, or evaluated by updating only some of the existing SQL constructs, or both.

Abstract: Techniques are provided for changing data for an XML construct in an SQL/XML compliant database management system (DBMS). The DBMS allows instances of XML type to represent XML constructs, such as XML documents, XML elements, XML attributes, and fragments of XML documents. An SQL statement is received that includes an XML operator that operates on a particular component in an instance of XML type. During execution of the SQL statement, the XML operator is evaluated by modifying content for the component without modifying the entire instance. For example, an XML delete operator deletes the particular component from the instance. Other XML operators include an insert operator, an insert-before operator, an append-child operator, and an update operator. During execution, these operators may be rewritten to operate on existing SQL constructs, or evaluated by updating only some of the existing SQL constructs, or both.

Abstract: Techniques for transferring a serialized image of data for an XML construct includes selecting a first format from multiple different XML serialization formats that represent, in a database system, data for XML constructs as a series of data units, such as a series of bytes representing characters, or a series of bits, bytes or octets representing binary values. A message is generated that includes a payload and a payload type field. The payload includes particular serialized data that represents particular data for a particular XML construct in the first format. The type field includes data that indicates the first format. The message is sent from a sending component of the database system to a different receiving component of the database system. These techniques allow the format selection to be based on characteristics of the sending or receiving components to make better use of the resources available to the two components.

Abstract: Techniques are provided for changing data for an XML construct in an SQL/XML compliant database management system (DBMS). The DBMS allows instances of XML type to represent XML constructs, such as XML documents, XML elements, XML attributes, and fragments of XML documents. An SQL statement is received that includes an XML operator that operates on a particular component in an instance of XML type. During execution of the SQL statement, the XML operator is evaluated by modifying content for the component without modifying the entire instance. For example, an XML delete operator deletes the particular component from the instance. Other XML operators include an insert operator, an insert-before operator, an append-child operator, and an update operator. During execution, these operators may be rewritten to operate on existing SQL constructs, or evaluated by updating only some of the existing SQL constructs, or both.

Abstract: Techniques for managing XML data in an SQL compliant DBMS include receiving an SQL statement. The SQL statement includes a particular operator that operates on a first instance of XML type that represents a first set of XML elements. During execution of the SQL statement, the particular operator is evaluated by generating an ordered collection of instances of XML type. Each different instance in the ordered collection is based on a different XML element from the first set; and there is an instance in the ordered collection for every XML element from either the first set or from the first set and its descendents. When descendents are included, each entry in the ordered collection indicates a level in the XML tree. In another aspect, an aggregate operator in the SQL statement operates on a collection of instances, with associated levels, to generate a single instance of XML type.

Abstract: Techniques for executing database commands include receiving a database command that includes an XML component operation that operates on an XML construct that is based on a first set of one or more relational database constructs. It is determined whether the XML component operation can be transformed to a relational database operation on a particular set of one or more relational database constructs of the first set, which does not involve the XML component operation. If it is determined that the XML component operation can be transformed, then the XML component operation is rewritten as a particular relational database operation that operates on the particular set and that does not involve the XML component operation. The particular relational database operation is evaluated. In another aspect, techniques include determining a primitive set of XML generation operations and replacing non-primitive XML generation operations with one or more operations from the primitive set.