This document defines an update facility that extends the XML Query language, XQuery. The XQuery Update Facility provides expressions that can be used to make persistent changes to instances of the XQuery 1.0 and XPath 2.0 Data Model.
This is a
Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
This document defines a facility for updating instances of the XQuery 1.0 and XPath 2.0
Data Model; the language is specified in the form of extensions to
Since the last version of this document, several significant changes have been made.
Several new update primitives have been added, removing the need for the
compatibility table by introducing new mappings from updating expressions onto
update primitives.
Considerable clarification of the handling of namespace bindings have been made.
The semantics of node deletion and of parentless node value replacement have
been clarified.
Finally, the XQueryX specification for the XQuery Update Facility has been added
in an appendix.
Additional information about changes made since the last version of this document
can be found at
Of the XQuery Update Facility documents, only this document,
XQuery Update Facility 1.0, is a Last Call document.
The XQuery Update Facility Requirements
Public Last Call comments on this document and its open issues are invited.
Comments on this document are due by 31 October 2007.
Comments on this document should be made in W3C's
This document was produced by a group operating under the
September 2005: First internal draft
November 2005: Second internal draft
27 January 2006: First public working draft
8 May 2006: Second public working draft
11 July 2006: Third public working draft
28 August 2007: Last Call working draft
This document defines the syntax and semantics of an extension
to
The XQuery Update Facility 1.0 provides facilities to perform any or all
of the following operations on an
Insertion of a node.
Deletion of a node.
Modification of a node by changing
some of its properties while preserving its
Creation of a modified copy of a node with a new
As described in
The basic building block of XQuery is the expression. XQuery 1.0 provides
several kinds of expressions that can be composed with each other in
arbitrary ways. An XQuery 1.0 expression takes one or more
XQuery Update Facility 1.0 introduces a new category of expression called an
The extensions to XQuery 1.0 provided by XQuery Update Facility 1.0 may be characterized as follows:
XQuery Update Facility 1.0 introduces five new kinds of expressions, called insert, delete, replace, rename, and transform expressions, and specifies the syntax and semantics of each new kind of expression.
XQuery Update Facility 1.0 classifies XQuery expressions into the following categories: The definition of an
XQuery Update Facility 1.0 defines the places where updating and non-updating expressions can be used. In so doing, it makes small extensions to the syntax and semantics of certain existing expressions.
XQuery Update Facility 1.0 defines the following extensions to the XQuery processing model:
In XQuery 1.0, the result of each expression is an
In the current specification, no expression returns both a non-empty
XQuery Update Facility 1.0 also defines a set of
upd:applyUpdates operation.
upd:applyUpdates is an example of an update routine.
If the outermost expression in a query returns a upd:applyUpdates is implicitly applied to this pending update list. This invocation of upd:applyUpdates may raise an error (see
upd:applyUpdates operation. XQuery Update Facility 1.0 currently defines an entire query as one snapshot.
This specification defines the semantics of updates to an
The Prolog is extended by adding a new kind of
Support for each of the three revalidation modes is implementation-defined; however, an implementation must support at least one of the three revalidation modes. If a revalidation declaration specifies a revalidation mode that is not supported by the current implementation, a static error is raised
The following definition is added to the XQuery static context
(documented in
strict, lax, or skip,
is a component of the static context that controls the behavior of the
upd:revalidate operation.
The following entry is added to the table of static context components
(documented in
Component: Revalidation mode
Default initial value: strict.
Can be overwritten by an implementation: Yes (implementation defined.)
Can be overwritten by a query: Yes, overwritable by declaration in query prolog.
Scope: Global.
Consistency rules: Must be strict, lax, or skip.
XQuery Update Facility 1.0 extends the syntax of
In general,
An insert expression is an node and nodes may be used interchangeably, regardless of how many nodes are actually inserted. The position of the inserted nodes is determined as follows:
If before (or after) is specified:
The inserted nodes become the preceding (or following) siblings of the target node.
If multiple nodes are inserted by a single insert expression, the nodes remain adjacent and their order is preserved.
If multiple groups of nodes are inserted by multiple insert expressions
in the same
If as first into (or as last into) is specified:
The inserted nodes become the first (or last) children of the target node.
If multiple nodes are inserted by a single insert expression, the nodes remain adjacent and their order is preserved.
If multiple groups of nodes are inserted by multiple insert expressions
in the same
If into is specified without as first or as last:
The inserted nodes become children of the target node.
If multiple nodes are inserted by a single insert expression, their order is preserved.
The positions of the inserted nodes are chosen so as not to interfere with the intended
position of nodes that are inserted with the specification before, after,
as first into, or as last into. For example, If node B is inserted "after node A",
no other node will be inserted between nodes A and B unless it is also
inserted "after node A".
Subject to the above constraints, the positions of the inserted nodes among the children of the target node are implementation-dependent.
Examples:
Insert a year element after the publisher of the first book.
Navigating by means of several bound variables, insert a new police report into the list of police reports for a particular accident.
The semantics of an insert expression are as follows:
$alist be the sequence of attribute nodes in the insertion sequence. Let $clist be the remainder of the insertion sequence, in its original order.
Either $alist or $clist or both may be empty.
The target expression must be a
If the result is an empty sequence,
If any form of into is specified,
the result must be a single element or document node; any other non-empty result raises a type error
If before or after
is specified, the result must be a single element, text, comment, or processing instruction node; any other non-empty result raises a type error
If before or after
is specified, the node returned by the target expression must have a non-empty parent property
Let
$target be the node returned by the target expression.
If $alist is not empty and any form of into is specified, the following checks are performed:
$target must be an element node
No attribute node in $alist may have a QName whose $target
If $alist is not empty and before or after is specified, the following checks are performed:
parent($target) must be an element node
No attribute node in $alist may have a QName whose parent($target)
The result of the insert expression is an empty
If as first into is specified, the
If $alist is not empty, upd:insertAttributes($target, $alist)
If $clist is not empty, upd:insertIntoAsFirst($target, $clist)
If as last into is specified, the
If $alist is not empty, upd:insertAttributes($target, $alist)
If $clist is not empty, upd:insertIntoAsLast($target, $clist)
If into is specified with neither as first nor as last, the
If $alist is not empty, upd:insertAttributes($target, $alist)
If $clist is not empty, upd:insertInto($target, $clist)
If before is specified, let $parent be the parent node of $target. The
If $alist is not empty, upd:insertAttributes($parent, $alist)
If $clist is not empty, upd:insertBefore($target, $clist)
If after is specified, let $parent be the parent node of $target. The
If $alist is not empty, upd:insertAttributes($parent, $alist)
If $clist is not empty, upd:insertAfter($target, $clist)
A delete expression deletes zero or more nodes from an node and nodes may be used interchangeably, regardless of how many nodes are actually deleted. A delete expression is an
Examples:
Delete the last author of the first book in a given bibliography.
Delete all email messages that are more than 365 days old.
The semantics of a delete expression are as follows:
The target expression must be a $tlist be the list of nodes returned by
the target expression.
A new $tnode in $tlist, the following upd:delete($tnode). The resulting
pending update list (together with an empty
Since node deletions do not become effective until the end of a
The upd:delete($tnode) primitive causes the given node to be detached from its parent after completion of the current query. If the given node has no parent, it is implementation-defined whether a dynamic error is raised
The effects of a delete expression on persistent storage (if any) are beyond the scope of this specification.
A replace expression is an value of
is specified.
If value of is not specified, a replace expression
replaces one node with a new sequence of zero or more nodes. The replacement nodes occupy the position in the node hierarchy that was formerly occupied by the node that was replaced. For this reason, an attribute node can be replaced only by zero or more attribute nodes, and an element, text, comment, or processing instruction node can be replaced only by zero or more element, text, comment, or processing instruction nodes. Example:
Replace the publisher of the first book with the publisher of the second book.
The semantics of this form of replace expression are as follows:
The expression following the keyword with must be a $rlist be the node sequence that results from this evaluation. If $rlist contains a document node, the document node is replaced in $rlist by its children.
The target expression must be a
If the result is an empty sequence,
If the result is non-empty and does not consist of a single element, attribute, text, comment, or processing instruction node,
If the result consists of a node whose parent property is empty,
Let
$target be the node returned by the target expression, and let $parent be its parent node.
If $target is an element, text, comment, or processing
instruction node, then $rlist must consist exclusively of zero or more element, text, comment, or processing instruction nodes
If $target is an attribute node, then:
$rlist must consist exclusively of zero or more attribute nodes
No attribute node in $rlist may have a QName whose $parent
The result of the replace expression is an empty upd:replaceNode($target, $rlist)
If value of is specified,
a replace expression is used to modify the value of a node while preserving
its
Increase the price of the first book by ten percent.
The semantics of this form of replace expression are as follows:
The expression following the keyword with must be a $text be the result of this step.
The target expression must be a
If the result is an empty sequence,
If the result is non-empty and does not consist of a single element, attribute, text, comment, or processing instruction node,
Let
$target be the node returned by the target expression.
If $target is an element node, the result of the replace
expression is an empty upd:replaceElementContent($target, $text)
If $target is an attribute, text, comment, or processing
instruction node, let $string be the string value of the text node
constructed in Step 1. If Step 1 did not construct
a text node, let $string be a zero-length string.
Then:
If $target is a comment node, and $string contains two adjacent hyphens or ends with a hyphen, a dynamic error is raised
If $target is a processing instruction node, and $string contains the substring "?>", a dynamic error is raised
In the absence of errors, the result of a replace expression is an empty upd:replaceValue($target, $string).
A rename expression replaces the name property of a
Examples:
Rename the first author element of the first book to principal-author.
Rename the first author element of the first book to the QName that is the value of the variable $newname.
The semantics of a rename expression are as follows:
The target expression must be a
If the result is an empty sequence,
If the result is non-empty and does not consist of a single element, attribute, or processing instruction node,
Let
$target be the node returned by the target expression.
$QName
be this expanded QName.
The following checks are performed for error conditions:
If $target is an element node, the "namespaces" property of $target must not include any namespace binding that $QName
If $target is an attribute node that has a parent, the "namespaces" property of parent($target) must not include any namespace binding that $QName
If $target is processing instruction node, $QName must not include a non-empty namespace prefix.
The result of the rename expression is an empty upd:rename($target, $QName).
The effects of a rename expression are limited to its target node. Attributes and descendants of the target node are not affected. If a global change of names or namespaces is intended, some form of explicit iteration must be used. The following example illustrates such a global change. The example operates on the node bound to variable $root and all its attributes and descendants, changing all QNames with the prefix abc to have a new prefix xyz and a new namespace URI http://xyz/ns.
A transform expression can be used to create modified copies of existing nodes in an
Examples:
Return a sequence consisting of all employee elements that have Java as a skill, excluding their salary child-elements:
The following example copies a node, modifies the copy, and returns both the original node and the modified copy:
No persistent changes to the underlying data result from this example.
A transform expression consists of three clauses, denoted by the keywords copy, modify, and return. The semantics of a transform expression are as follows:
The copy clause contains one or more variable bindings, each of which consists of a variable name and an expression called the
The source expression must be a
The node returned by the source expression is a new node whose
The variable name is bound to the node returned by the source expression. The scope of this variable binding includes all subexpressions of the containing transform expression that appear after the variable binding clause, including the source expressions of later variable bindings, but it does not include the source expression to which the current variable name is bound.
The modify clause must contain either an ( ), or a call to the fn:error function; otherwise a static error is raised modify clause is evaluated, resulting in a $pul be the pending update list generated by this step.
The following upd:applyUpdates($pul). The effect of this operation is to make the updates specified in the modify clause effective on the copied nodes.
In the event of incompatible updates, the upd:applyUpdates operation may raise an error, as described in
The return clause must contain a return clause is evaluated, and its result is the result of the transform expression. During evaluation of the return clause, changes applied to copied nodes by the preceding step are visible.
The rules defining compatibility of
The effect of these rules is as follows:
If any node is affected by more than one rename expression within a
If any node is affected by more than one replace expression (without value of being specified) within a
If any node is affected by more than one replace value of expression within a
Within a given E is the target of a replace value of expression, and the children of E are also modified by other expressions, the final children of E are determined by the replace value of expression. For example:
Suppose that $A is bound to an element node that has a child element named B. Suppose that the following expressions are evaluated in the same
The expressions on the left and right side of the comma can be evaluated in any order. No error is raised. At the end of the $A will consist of a single text node with the content "Goodbye".
XQuery Update Facility 1.0 provides extensions to the semantics of several existing kinds of XQuery expressions, as specified in this section.
The syntax of the FLWOR expression is not changed. Its semantics are extended as follows:
If a for,
let, where, or order by
clause contains an
If the return clause contains a
If the return clause contains an
The semantics of the for,
let, where, and order by
clauses are as specified in Section 3.8 of
For each tuple
generated by the previous step, the updating expression in the
return clause is evaluated, resulting in a
All the upd:mergeUpdates
operation. The resulting merged pending update list is the
result of the FLWOR expression.
In the event of incompatible updates, the upd:mergeUpdates operation may raise an error, as described in
The following example illustrates the use of an updating expression in a FLWOR expression:
Update an inventory of parts according to a set of changes provided in the bound variable $changes. Both /inventory and $changes contain a set of part elements, each with a partno and a quantity.
The syntax of the typeswitch expression is not changed. Its semantics are extended as
follows (the term "branch" refers to any case or default clause in the typeswitch expression):
If the operand expression of a typeswitch is an
If any branch contains an
If the typeswitch expression is a
If the typeswitch expression is an ( ), or a call to the fn:error function; otherwise a static error is raised return
clause of the effective case (or default) is then evaluated, resulting
in a
The semantics of
conditional expressions are extended as follows (the term "branch" refers to the then and else clauses in the conditional expression):
If the if-clause contains an
If either branch contains an
If the conditional expression is a
If the conditional expression is an ( ), or a call to the fn:error function; otherwise a static error is raised then or else
clause is selected and evaluated as specified in Section 3.10 of
The following example illustrates the use of updating expressions in a conditional expression:
If the element bound to variable $e has a last-updated attribute, update its value to the current date; otherwise insert such an attribute.
The semantics of
comma expressions (composed of one or more expressions concatenated by the comma operator, as described in Section 3.3.1 of
If any operand of the comma expression is an
If the comma expression is a
If the comma expression is an ( ), or a call to the fn:error function; otherwise a static error is raised upd:mergeUpdates
operation. The resulting merged
The following example illustrates the use of an updating comma expression:
This example makes the value of an element empty and gives the element an xsi:nil="true" attribute. Both of these operations may be necessary in order to preserve the validity of the element.
The semantics of a parenthesized expression (any XQuery expression enclosed in parentheses) are extended as follows:
The category of a parenthesized expression is the same as the category of its operand expression, which may be an ( ) is a
The syntax of a function declaration is extended to include an optional keyword: updating.
If updating is not specified:
If external is not specified, the EnclosedExpr in the function declaration must be a
If external is specified, the external function must not return a non-empty
If updating is specified:
A return type must not be specified
If external is not specified, the EnclosedExpr in the function declaration must be an ( ), or a call to the fn:error function; otherwise a static error is raised
If external is specified, the external function may return a non-empty
The means by which an external function returns an
The following example illustrates a declaration of an updating function.
This function takes an element, a QName, and an atomic value. If the given element has an attribute with the given QName, the function updates the attribute with the given value; otherwise it inserts a new attribute with the given name and value.
The semantics of a function call are extended as follows:
The function call is evaluated as specified in Section 3.1.5 of updating keyword, the function call is an updating keyword, the function call is a
The semantics of all XQuery expressions other than FLWOR expressions, typeswitch expressions, conditional expressions, comma expressions, parenthesized expressions, and function calls are extended as follows:
If any operand of this expression is an
In addition, the initializing expression of a variable declaration in a Prolog may not be an
XQuery Update Facility 1.0 provides extensions to XQuery built-in function library, as specified in this section.
Summary: Stores a document or element to the location specified by $uri.
This function is normally invoked to create
a resource on an external storage system such as a file system or a
database.
If $node is not a document node or an element node, and the implementation does not support fn:put on the given node kind, a dynamic error is
raised
If
$uri is not a valid lexical representation of the xs:anyURI type, a dynamic error is
raised $uri is a relative URI Reference, it is resolved
relative to the value of the base URI property in the static
context.
The semantics of fn:put are implementation-defined,
since they occur completely outside the domain of XQuery. The intent is that, if fn:put is invoked on a document node and no error is raised, a
subsequent query can access the stored document by invoking
fn:doc with the same URI.
The results of fn:put do not become effective until after completion of the query containing the fn:put function--that is, until after completion of the upd:applyUpdates operation invoked by the outermost expression in the current query. The fn:put function has no effect on the current query. (For example, it does not change the set of available documents or collections seen by the current query.)
This section describes the update operations defined by XQuery Update Facility 1.0. Although these update operations are described using a functional notation, they are not true functions because many of them have no return value. These update operations are used in defining the semantics of XQuery expressions, but they are not directly available to users.
Update operations consist of
The update primitives described in this section may be held on upd:applyUpdates routine.
Inserts $content immediately before $target.
$target must be an element, text, processing
instruction, or comment node with a non-empty parent property. $content must be a sequence containing only element, text, processing instruction,
and comment nodes.
Effects on nodes in $content:
For each node in $content, the parent property is set to parent($target).
If the type-name property of parent($target) is xs:untyped, then upd:setToUntyped() is invoked on each element or attribute node in $content.
Effects on parent($target):
The children property of parent($target) is modified to add the nodes in $content just before $target, preserving their order.
If at least one of the nodes in $content is an element or text node, upd:removeType(parent($target)) is invoked.
Inserts $content immediately after $target.
$target must be an element, text, processing
instruction, or comment node with a non-empty parent property. $content must be a sequence containing only element, text, processing instruction,
and comment nodes.
The semantics of upd:insertAfter are identical to the semantics of upd:insertBefore, except that Rule 2a is changed as follows:
The children property of parent($target) is modified to add the nodes in $content just after $target, preserving their order.
Inserts $content as the children of $target, in an implementation-dependent position.
$target must be an element or document node. $content must be a sequence containing only element, text, processing instruction,
and comment nodes.
The semantics of upd:insertInto are identical to the semantics of upd:insertBefore, except that $target is substituted everywhere for parent($target), and Rule 2a is changed as follows:
The children property of $target is changed to include the nodes in $content in implementation-dependent positions, preserving their relative order.
Inserts $content as the first children of $target.
$target must be an element or document node. $content must be a sequence containing only element, text, processing instruction,
and comment nodes.
The semantics of upd:insertIntoAsFirst are identical to the semantics of upd:insertBefore, except that $target is substituted everywhere for parent($target), and Rule 2a is changed as follows:
The children property of $target is changed to include the nodes in $content as the first children, preserving their order.
Inserts $content as the last children of $target.
$target must be an element or document node. $content must be a sequence containing only element, text, processing instruction,
and comment nodes.
The semantics of upd:insertIntoAsLast are identical to the semantics of upd:insertBefore, except that $target is substituted everywhere for parent($target), and Rule 2a is changed as follows:
The children property of $target is changed to include the nodes in $content as the last children, preserving their order.
Inserts $content as attributes of $target.
None
Error checks:
If the QNames of any two attribute nodes in $content have
If the QName of any attribute node in $content has an $target, a dynamic error is raised
For each node $A in $content:
The parent property of $A is set to $target.
If the type-name property of $target is xs:untyped, then upd:setToUntyped($A) is invoked.
The following properties of $target are changed:
attributes: Modified to include the nodes in $content.
namespaces: Modified to include namespace bindings for any attribute namespace prefixes in $content that did not already have bindings.
upd:removeType($target) is invoked.
None
If $target has no parent, the $target had no parent before execution of the query began.
If $target has a parent node $P, then:
The parent property of $target is set to empty.
If $target is an attribute node, the attributes property of $P is modified to remove $target.
If $target is a non-attribute node, the children property of $P is modified to remove $target.
If $target is an element, attribute, or text node, and $P is an element node, then upd:removeType($P) is invoked.
Deleted nodes are detached from their parent nodes; however, a node deletion has no effect on variable bindings or on the set of available documents or collections during processing of the current query.
Multiple upd:delete operations may be applied to the same node during execution of a query; this is not an error.
Replaces $target with $replacement.
$target must be a node that has a parent. If $target is an attribute node, $replacement must consist of zero or more attribute nodes. If $target is an element, text, comment, or processing instruction node, $replacement must be consist of zero or more element, text, comment, or processing instruction nodes.
Error checks:
If the QNames of any two attribute nodes in $replacement have
If the QName of any attribute node in $replacement has an parent($target), a dynamic error is raised
Effects on nodes in $replacement:
For each node in $replacement, the parent property is set to parent($target).
If the type-name property of parent($target) is xs:untyped, then upd:setToUntyped() is invoked on each element node in $replacement.
Effect on $target:
The parent property of $target is set to empty.
Effects on parent($target):
If $target is an attribute node, the attributes property of parent($target) is modified by removing $target and adding the nodes in $replacement (if any).
If $target is an attribute node, the namespaces property of parent($target) is modified to include namespace bindings for any attribute namespace prefixes in $replacement that did not already have bindings.
If $target is an element, text, comment, or processing instruction node, the children property of parent($target) is modified by removing $target and adding the nodes in $replacement (if any) in the former position of $target, preserving their order.
upd:removeType(parent($target)) is invoked.
Replaces the string value of $target with $string-value.
$target must be an attribute, text, comment, or processing instruction node.
If $target is an attribute node:
string-value of $target is set to $string-value.
upd:removeType($target) is invoked.
If $target is a text, comment, or processing instruction node: content of $target is set to $string-value.
If $target is a text node that has a parent, upd:removeType(parent($target)) is invoked.
Replaces the existing children of the element node $target by the optional text node $text. The attributes of $target are not affected.
None.
For each node $C that is a child of $target, the parent property of $C is set to empty.
The parent property of $text is set to $target.
Effects on $target:
children is set to consist exclusively of $text. If $text is an empty sequence, then $target has no children.
typed-value and string-value are set to the content property of $text. If $text is an empty sequence, then typed-value is an empty sequence and string-value is an empty string.
upd:removeType($target) is invoked.
Changes the node-name of $target to $newName.
$target must be an element, attribute, or processing instruction node.
If $target is an element node:
node-name of $target is set to $newName.
upd:removeType($target) is invoked.
If $newName has an namespaces property of $target, a dynamic error is raised
The namespaces property of $target is modified to include a namespace binding derived from $newName, if this binding did not already exist.
If $target is an attribute node:
node-name of $target is set to $newName.
upd:removeType($target) is invoked.
If $newName is xml:id, the is-id property of $target is set to true.
If $target has a parent, and $newName has an namespaces property of parent($target), a dynamic error is raised
If $target has a parent, the namespaces property of parent($target) is modified to include a namespace binding derived from $newName, if this binding did not already exist.
If $target is a processing instruction node, its target property is set to the local part of $newName.
At the end of a upd:applyUpdates.
Merges two
None.
The two
Optionally, upd:mergeUpdates may raise a dynamic error if any of the following conditions are detected:
Two or more upd:rename primitives on the merged list have the same target node
Two or more upd:replaceNode primitives on the merged list have the same target node
Two or more upd:replaceValue primitives on the merged list have the same target node
Two or more upd:replaceElementContent primitives on the merged list have the same target node
None.
This routine ends a
Checks the update primitives on $pul for compatibility. Raises a dynamic error if any of the following conditions are detected:
Two or more upd:rename primitives on $pul have the same target node
Two or more upd:replaceNode primitives on $pul have the same target node
Two or more upd:replaceValue primitives on $pul have the same target node
Two or more upd:replaceElementContent primitives on $pul have the same target node
The semantics of all the $pul are made effective, in the following order:
First, all upd:insertInto, upd:insertAttributes, upd:replaceValue, and upd:rename primitives are applied.
Next, all upd:insertBefore, upd:insertAfter, upd:insertIntoAsFirst, and upd:insertIntoAsLast primitives are applied.
Next, all upd:replaceNode primitives are applied.
Next, all upd:replaceElementContent primitives are applied.
Finally, all upd:delete primitives are applied.
If, as a net result of the above steps, the children property of some node contains adjacent text nodes, these adjacent text nodes are merged into a single text node. The string-value of the resulting text node is the concatenated string-values of the adjacent text nodes, with no intervening space added. The
If, as a net result of the above steps, the children property of some node contains an empty text node, that empty text node is deleted from the children property.
For each document or element node $top that was upd:revalidate($top) is invoked.
If the resulting
For example, a data model constraint violation might occur if multiple attributes with the same parent have the same qualified name (see
The upd:applyUpdates operation is atomic with respect to the data model. In other words, if upd:applyUpdates terminates normally, the resulting upd:applyUpdates raises an error, the resulting
The results of implementation-dependent error conditions such as exceeding resource limits are beyond the scope of this specification.
Propagation of XDM changes to an underlying persistent store is beyond the scope of this specification. For example, the effect on persistent storage of deleting a node that has no parent is beyond the scope of this specification.
$top must be a document node or an element node.
Schema validation is applied to the subtree rooted at $top in order to recover the types of updated nodes while preserving their
If skip, upd:revalidate performs no action. Otherwise:
If lax, define $topV as the result of the XQuery expression validate lax {$top}. If strict, define $topV as the result of the XQuery expression validate strict {$top}. During computation of $topV, it is necessary to maintain a mapping between each node in $topV and the corresponding node (if any) in the subtree rooted at $top (this mapping is maintained in an implementation-dependent way.)
This step may raise an error $top is found to be invalid.
Some of the nodes in $topV (for example, default attributes generated by the validation process) may have no corresponding nodes in $top.
For each node $nV in $topV that has a corresponding node $n in $top, replace the following properties of $n with the corresponding properties of $nV: type-name, typed-value, string-value, is-id, is-idrefs, namespace-bindings, nilled.
For each node $nV in $topV that does not have a corresponding node in $top, insert the node $nV into the subtree rooted at $top as a child or attribute of the node corresponding to the parent of $nV.
The result of upd:revalidate is to modify the properties of the nodes rooted at $top and possibly to add some new nodes to this subtree. When the revalidation process is complete, $topV can be discarded.
After revalidation, the type annotations of the nodes in the validated subtree are consistent with their content. It is expected that implementations will optimize the revalidation process by taking into account which nodes have been modified since they were last validated.
$N must be an element or attribute node
This routine is applied to a node whose name or content has been modified, in order to remove specific type information from the node and its ancestors, pending revalidation.
If $N is an element node, its properties are changed as follows:
If type-name is not equal to xs:untyped, then
If the parent of type-name is set to xs:anyTypeN is an element node, then upd:removeType(parent($N)) is invoked.
string-value is set equal to the concatenated contents of the text node descendants, in document order.
typed-value is set equal to the string-value property, as an instance of xs:untypedAtomic.
The string-value and/or typed-value are stored or computed dynamically.
nilled, is-id, and is-idrefs are set to false.
If $N is an attribute node, its properties are changed as follows:
type-name is set to xs:untypedAtomic.
typed-value is set equal to the string-value property, as an instance of xs:untypedAtomic.
is-id and is-idrefs are set to false.
If $N has a parent, upd:removeType(parent($N)) is invoked.
The topmost ancestor of $N is
$N must be an element or attribute node
This routine is applied to a node that has been inserted into an untyped context, which requires that the node and its descendants be untyped as well.
If $N is an element node, its properties are changed as follows:
type-name is set to xs:untyped.
typed-value is set equal to the string-value property, as an instance of xs:untypedAtomic.
The string-value and/or typed-value are stored or computed dynamically.
nilled, is-id, and is-idrefs are set to false.
upd:setToUntyped() is invoked on the attributes and child element nodes of $N.
If $N is an attribute node, its properties are changed as follows:
type-name is set to xs:untypedAtomic.
typed-value is set equal to the string-value property, as an instance of xs:untypedAtomic.
is-id and is-idrefs are set to false.
XQuery 1.0 includes an optional static typing feature. This section
describes the static typing feature for the
XQuery Update Facility 1.0. Implementations of this specification that support
optional static typing must implement the following static typing
rules, along with the XQuery 1.0 static typing rules defined in
The concepts and notations used in this specification are the same
as those used to define the static typing feature for XQuery 1.0. For
convenience, we recall here some of the main concepts and
notations. We refer the reader to
The static typing feature for the XQuery Update Facility 1.0 is defined based on a
processing model similar to the one of XQuery 1.0. We first define the
XQuery Update Facility 1.0
Normalization rules map expressions in the XQuery Update Facility 1.0 into expressions in the XQuery Update Facility 1.0 Core. They are written as follows.
The static semantics is specified through a
The judgment
holds when, in the static environment statEnv, the
expression
The static environment is the same as the one defined in
| statEnv.revalidationMode |
|
We extend the
XQuery Core defined in
The core grammar production for IfExpr can be found in
The core grammar production for OrExpr can be found in
The core grammar production for FLWORExpr can be found in
The core grammar production for QuantifiedExpr can be found in
The core grammar production for TypeswitchExpr can be found in
The core grammar production for VarName can be found in
In addition to the normalization rules defined in
Revalidation declarations are left unchanged through normalization.
The revalidation declaration modifies the revalidation mode in the static context.
In addition to the normalization and static typing rules
defined in
The following normalization rules applies to insert expressions. Note that whether the expression is written using the 'nodes' or 'node' modifier, the normalized expression always uses the 'nodes' modifier.
item-sequence-to-node-sequence(Where item-sequence-to-node-sequence is the special function used
for computing element content and is defined in
The static typing rule for insert depends on whether it is an
insert into, or an insert before or
after.
In the case of an insert into, the inference
depends on whether the target node is an element or a document
node (in which case it does not allow attribute nodes to be
inserted). This is expressed by the two following rules.
emptyemptyIn the case of an insert before or
after, the type of the target node must be either
an element, text, comment or processing-instruction node. This
is expressed by the following rule.