Technique of using XMLType tree as the type infrastructure for XML

• US 20060031233A1
• Filed: 01/26/2005
• Published: 02/09/2006
• Est. Priority Date: 08/06/2004
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Manikutty, Anand, Arora, Vikas, Warner, James W., Krishnaprasad, Muralidhar, Liu, Zhen Hua
• Granted Patent: US 7,685,137 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 40/143 Markup, e.g. Standard Generalized Markup Language [SGML] or Document Type Definition [DTD]

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.

Claims

1. A method for generating a type representation of an XMLType structure, comprising the steps of:

generating, based on a source of XMLType data type information, an XMLType type tree of nodes representing the type structure of an XMLType instance; and

wherein the step of generating an XMLType type tree of nodes includes;

generating a leaf item node; and

generating as a certain node, with one or more children nodes that include said leaf item node, either a;

composite element item node that corresponds to an element node XMLType instance,

composite document item node that corresponds to a document node XMLType instance,

operator node that indicates how the one or more children nodes are grouped as a sequence, choice, or permutation, or

aggregate node with an aggregate quantifier set to indicate a cardinality restriction on the one or more children nodes.

2. The method of claim 1, wherein the source of XMLType data type information includes heterogonous sources of XMLType data type information.

3. The method of claim 1, wherein the source of XMLType data type information includes XMLType instances generated by an SQL expression returning XMLType.

4. The method of claim 1, wherein the source of XMLType data type information includes XMLType instances conforming to an XML schema.

5. The method of claim 1, wherein:

the source of XMLType data type information is based on an SQL/XML function converting an object type to XMLType;

generating a composite node includes generating a composite node that corresponds to the object type; and

the steps further include generating an operator node with one or more nodes that each correspond to a member attribute of the object type.

6. The method of claim 1, wherein:

the source of XMLType data type information is based on an SQL/XML function converting a collection type to XMLType;

generating an aggregate node with aggregate quantifier set to zero or more; and

the one or more nodes that descend from the aggregate node include one or more nodes that each correspond to the collection element type.

7. The method of claim 1, wherein:

XMLType output of a first function is an input XMLType argument of a second function;

the steps further include generating a second XMLType tree of nodes representing the output of the first function; and

the step of generating an XMLType tree of nodes is based on the second XMLType tree of nodes.

8. The method of claim 1, wherein the steps further include registering a set of callback interface functions associated with a user defined opaque type, the set of callback interface functions including a function getXMLTypeTree( ) that returns an XMLType type tree of nodes that describes the type structure of XMLType converted from the user defined opaque type.

9. The method of claim 1, wherein the tree of nodes describes the type tree of XMLType input parameters or output return values of a user-defined function, the type tree can be transient in memory or persisted on disk

10. The method of claim 1, wherein:

the tree of nodes contains a first subset of one or more nodes; and

generating based on one or more rules that define equivalent sets of nodes, another tree of nodes that include in lieu of the first subset of nodes, a second subset of one or more nodes that are the equivalent to the first subset of one or more nodes.

11. The method of claim 10, wherein the one or more rules include at least one rule from a set of algebra rules that include:

(1) empty*=empty,

(2) empty?=empty,

(3) empty+=empty, and

(4) (T1, . . . , empty, . . . Tn)=(T1, . . . , Tn).

12. The method of claim 10, wherein the one or more rules include at least one rule from a set of algebra rules that include:

(1) (T1|T2)*=T1*|T2*,

(2) (T1|T2)?=T1?|T2?, and

(3) (T1|T2)+=T1+|T2+.

13. The method of claim 10, wherein the one or more rules include at least one rule from a set of algebra rules that include:

(1) (T*)*=T*,

(2) (T*)?=T*,

(3) (T*)+=T*,

(4) (T?)?=T,

(5) (T?)*=T*,

(6) (T?)+=T*,

(7) (T+)?=T*,

(8) (T+)+=T+, and

(9) (T+)*=T*.

14. The method of claim 10, wherein the one or more rules include at least one rule from a set of algebra rules that include:

(1) T1&

T2=(T1, T2)|(T2, T1),

(2) T|T=T, and

(3)T&

T=T, T.

15. The method of claim 10, wherein the one or more rules include at least one rule from a set of algebra rules that include:

(1) T?=empty|T, and

(2) T*=empty|T+

16. The method of claim 1, wherein the source of data type information includes an SQL expression returning XMLType.

17. The method of claim 16, wherein:

the SQL expression casts an SQL scalar type as an XMLType; and

the step of generating an XMLType type tree of nodes includes generating, based on the SQL scalar type, a leaf item node that corresponds to an XML atomic value.

18. The method of claim 16, wherein:

the SQL expression includes an SQL/XML function that converts an SQL object type to XMLType; and

the step of generating an XMLType type tree of nodes includes generating an element node that corresponds to the object type with a descending sequence operator node, each child of the sequence operator node corresponding to a member attributes of the object type.

19. The method of claim 16, wherein:

the SQL expression includes an SQL/XML function that converts an SQL collection type to XMLType; and

the step of generating an XMLType type tree of nodes includes generating an 5 aggregate node with an aggregate quantifier set to zero or more and descendant nodes of the aggregate node for the collection element type.

20. The method of claim 16, wherein:

the SQL expression includes an XMLElement( ) SQL/XML function returning sequence option; and

the step of generating an XMLType type tree of nodes includes generating an element node with one or more descendants.

21. The method of claim 16, wherein:

the SQL expression includes an XMLElement( ) SQL/XML function returning content option; and

the step of generating an XMLType type tree of nodes includes generating a document node with an element node and descendants of the element node.

22. The method of claim 16, wherein:

the SQL expression includes an XMLAttribute( ) SQL/XML function; and

the step of generating an XMLType type tree of nodes includes generating an attribute node.

23. The method of claim 16, wherein:

the SQL expression includes an XMLCONCAT( ) SQL/XML function returning sequence option; and

the step of generating an XMLType type tree of nodes includes generating a sequence operator node with one or more descendants generated from the input SQL expressions for XMLCONCAT( ) function.

24. The method of claim 16, wherein:

the SQL expression includes an XMLCONCAT SQL/XML function returning content option; and

the step of generating an XMLType type tree of nodes includes generating a document node with descendants constructed from input SQL expressions for the XMLCONCAT( ) SQL/XML function.

25. The method of claim 16, wherein:

the SQL expression includes an XMLAgg( ) SQL/XML function returning sequence option; and

the step of generating an XMLType type tree of nodes includes generating an aggregate node having aggregate quantifier set to zero or more and descendant nodes generated from input SQL expressions of the XMLAgg( ) SQL/XML function.

26. The method of claim 16, wherein:

the SQL expression includes an XMLAgg( ) SQL/XML function returning content option; and

the step of generating an XMLType type tree of nodes includes generating a document node with an aggregate node having an aggregate quantifier set to zero or more and descendant nodes generated from input SQL expressions of the XMLAgg( ) SQL/XML function.

27. The method of claim 16, wherein:

the SQL expression includes an SQL CASE function; and

the step of generating an XMLType type tree of nodes includes generating a choice operator node with one or more children, each child of the choice operator node generated based on an SQL expression of each branch of the CASE function.

28. The method of claim 16, wherein:

the SQL expression includes an SQL/XML function which uses XPath query; and

the step of generating an XMLType type tree of nodes includes generating an XMLType type tree based on data typing analysis performed during query compile time of the XPath.

29. The method of claim 16, wherein:

the SQL expression includes an XMLQuery( ) SQL/XML function embedding an XQuery query; and

the step of generating an XMLType type tree of nodes includes generating an XMLType type tree based on data typing analysis performed during query compile time of the XPath.

30. The method of claim 16, wherein:

the SQL expression includes an XMLType expression based on an XML schema; and

the step of generating an XMLType type tree of nodes includes generating an XMLType type tree that represents the XML schema.

31. The method of claim 16, wherein:

the SQL expression includes an SQL function returning an XMLType whose structure is unknown during query compile time; and

generating an XMLType type tree of an aggregate node includes generating an aggregate quantifier set to zero or more and, as a child of the aggregate node, a choice operator node with one or more descendant leaf item nodes.

32. A method for generating a type representation of a hierarchical value that includes a hierarchy of nodes, comprising:

generating, based on a source of data type information, a tree of nodes representing the type structure of the hierarchical value; and

wherein the step of generating a tree of nodes includes;

generating a leaf node; and

generating as a certain node, with one or more children nodes that include said leaf node, either a;

operator node that indicates how the one or more children nodes are grouped as a sequence, choice, or permutation, or

aggregate node with an aggregate quantifier set to indicate a cardinality restriction on the one or more children nodes.