Update xmltype oracle

The XML document that is the target of the insertion can be schema-based or non-schema-based. Example inserts a new LineItem element as a child of element LineItems. Note that it uses the Oracle XQuery pragma ora:child-element-name to specify the name of the inserted child element as LineItem.

If the XML data to be updated is XML schema-based and it refers to a namespace, then the data to be inserted must also refer to the same namespace. Otherwise, an error is raised because the inserted data does not conform to the XML schema. Be aware that using XQuery Update to update XML schema-based data results in an error being raised if you try to store the updated data back into an XML schema-based column or table.

Example is the same as Example , except that the LineItem element to be inserted refers to a namespace. This assumes that the relevant XML schema requires a namespace for this element. Example inserts a LineItem element before the first LineItem element. Example inserts a Date element as the last child of an Action element. Example deletes the LineItem element whose ItemNumber attribute has value Example creates a view of table purchaseorder.

A SQL query that involves XQuery expressions can often be automatically rewritten optimized in one or more ways. This optimization is referred to as XML query rewrite or optimization.

XPath expressions are a proper subset of XQuery expressions. The rewritten SQL statement can also make use of any B-tree indexes on the underlying data structures.

This can take place for both queries and update operations. As with database queries generally, you determine whether tuning is required by examining the execution plan for a query.

If the plan is not optimal, then consult the following documentation for specific tuning information:. In addition, be aware that the following expressions can be expensive to process, so they might add performance overhead when processing large volumes of data:. Several competing optimization possibilities can exist for queries with XQuery expressions, depending on various factors such as the XMLType storage model and indexing that are used.

By default, Oracle XML DB follows a prioritized set of rules to determine which of the possible optimizations should be used for any given query and context. This behavior is referred to as rule-based XML query rewrite. In this mode, Oracle XML DB estimates the performance of the various XML optimization possibilities for a given query and chooses the combination that is expected to be most performant.

Example shows the optimization of XMLTable in the same context. Here again is the query of Example , together with its execution plan, which shows that the query has been optimized. The XQuery result is never materialized. Instead, the underlying storage columns for the XML collection element LineItem are used to generate the overall result set. This example traverses table oe.

The XMLTable expression is evaluated for each purchase-order document. The UnitPrice attribute of collection element LineItem is an appropriate index target. Instead of using table purchaseorder from sample database schema HR , you could manually create a new purchaseorder table in a different database schema with the same properties and same data, but having OCTs with user-friendly names.

With this index defined, the query of Example results in the following execution plan, which shows that the XMLTable expression has driven the overall evaluation. You can examine an execution plan for your SQL code to determine whether XQuery optimization occurs or the plan is instead suboptimal.

When this mode is on, the plan of execution is automatically checked for XQuery optimization, and if the plan is suboptimal then an error is raised and diagnostic information is written to the trace file indicating which operators are not rewritten. The main advantage of XMLOptimizationCheck is that it brings a potential problem to your attention immediately. For this reason, you might find it preferable to leave it turned on at all times. Then, if an application change or a database change for some reason prevents a SQL operation from rewriting, execution is stopped instead of performance being negatively impacted without your being aware of the cause.

Users of older releases directly manipulated event to obtain XQuery optimization information. Only the event is available to Java users. You can improve the performance of fn:doc and fn:collection queries over the Oracle XML DB Repository, by linking them to the actual database tables that hold the repository data being queried.

When repository XML data is stored object-relationally or as binary XML, queries that use fn:doc and fn:collection are evaluated functionally; that is, they are not optimized to access the underlying storage tables directly.

To improve the performance of such queries, you must link them to the actual database tables that hold the repository data being queried. You can do that in either of the following ways:. These SQL functions reference repository resources in a performant way.

Both methods have the same effect. Oracle recommends that you use the ora:defaultTable pragma because it lets you continue to use the XQuery standard functions fn:doc and fn:collection and it simplifies your code. You can use Oracle XQuery extension-expression pragma ora:defaultTable to improve the performance of querying repository data.

Oracle XQuery extension-expression pragma ora:defaultTable lets you specify the default table used to store repository data that you query. Example illustrates this; the query is rewritten automatically to what is shown in Example For clarity of scope Oracle recommends that you apply pragma ora:defaultTable directly to the relevant document or collection expression, fn:doc or fn:collection , rather than to a larger expression.

XQuery function fn:data is used here to atomize its argument, in this case returning the XMLRef node's typed atomic value. In Example , the various FLWOR clauses perform these operations: The outer for iterates over the sequence of XML elements returned by fn:collection : each element corresponds to a row of relational table oe.

See Also: Example for the execution plan of Example The result is shown here pretty-printed, for clarity. This produces the following result. McCain 32 rows selected. Place the text that follows the semicolon on the same line. McEwen 9 Ellen S. Abel 4 Sarah J. Bell 13 William M. If a performance is critical b it truly is just a logging facility it would seem to me that why bother with all the XML manipulation? Rating 2 ratings Is this answer out of date?

You can also catch regular content via Connor's blog and Chris's blog. Or if video is more your thing, check out Connor's latest video and Chris's latest video from their Youtube channels. And of course, keep up to date with AskTOM via the official twitter account.

Questions efficient appending to XMLType column. Question and Answer. Thanks for the fast response, Connor. You can use the index mechanism to identify individual elements in case of repeated elements in an XML document. If you have an XML document such as that in Example , then you can use:. XML schema-based documents. For documents based on XML schema, if Oracle Database can infer the type of the return value, then a scalar value of the appropriate type is returned.

Non-schema-based documents. With XML schema-based content, extractValue returns the underlying datatype in most cases. CLOB values are returned directly. This can help maintain consistency between different queries regardless of whether the queries can be rewritten. SQL function extractValue lets you extract the desired value more easily than extract ; it is a convenience function.

You can use it in place of extract. If the node at path has only one child and that child is a text node, then you can leave the text test off of the XPath argument: extractValue x, 'path'. If not, an error is raised if you leave off text. It cannot return XML nodes or mixed content. An error is raised if extractValue cannot return a scalar value. If the length is greater than 4K, a run-time error is raised. If XML schema information is available at query compile time, then the datatype of the returned value is based on the XML schema information.

If the XPath argument identifies a node, then the node must have exactly one text child or an errror is raised. The text child is returned. For example, this expression extracts the text child of the Reference node:.

This query extracts the scalar value of the Reference node. This example inserts two rows into the purchaseorder table, then queries data in those rows using extractValue.

A local XMLType instance is used to store transient data. This example extracts data from an XML purchase-order document, and inserts it into a SQL relational table using extract. This example extracts data from an XML purchase-order document, and inserts it into a relational table using SQL function extractValue.

This example extracts the purchase-order name from the purchase-order element, PurchaseOrder , for customers with " ll " double L in their names and the word " Shores " in the shipping instructions.

The result may be a set of nodes, a singleton node, or a text value. You can determine whether the result is a fragment using the isFragment method on the XMLType instance. For CLOB -based storage, an update effectively replaces the entire document.

This can be created in any of the following ways:. This is also called partial updating. These SQL functions are described in the following sections:. In particular, do not use function updateXML to insert or delete XML data by replacing a parent node in its entirety; this will work, but it is less efficient than using one of the other functions, which perform more localized updates.

These are all pure functions, without side effects. Each of these functions can be used on XML documents that are either schema-based or non-schema-based. In the case of schema-based XML data, these SQL functions perform partial validation on the result, and, where appropriate, argument values are also checked for compatibility with the XML schema. The XML document that is the target of the update can be schema-based or non-schema-based. A copy of the input XMLType instance is modified and returned; the original data is unaffected.

One or more pairs of xpath and replacement parameters:. These can be nodes of any kind. If xpath matches an empty sequence of nodes, then no replacement is done; target-data is returned unchanged and no error is raised.

The datatype of replacement must correspond to the data to be replaced. SQL function updateXML can be used to replace existing elements, attributes, and other nodes with new values.

It is not an efficient way to insert new nodes or delete existing ones; you can only perform insertions and deletions with updateXML by using it to replace the entire node that is parent of the node to be inserted or deleted. The entire document is updated, not just the part that is selected. The type and namespace properties of the element are retained.

See Example If you update an attribute value to NULL , the value appears as the empty string. If you update the text node of an element to NULL , the content text of the element is removed; the element itself remains, but is empty.

The Description element and the Quantity attribute of the LineItem element whose Part element has attribute Id value The order of updates is determined by the order of the XPath expressions in left-to-right order.

Each successive XPath works on the result of the previous XPath update. When you update a text node inside an element to NULL , you remove that text node from the element.

Furthermore, text nodes can appear only inside simpleType elements when DOM fidelity is not preserved, since there is no positional descriptor with which to store mixed content. When you update an attribute node to NULL , you remove the attribute from the element. If particular conditions are met, then the function call is rewritten to update the object-relational columns directly with the values.

The XML document that is the target of the insertion can be schema-based or non-schema-based. If parent-xpath matches an empty sequence of element nodes, then no insertion is done; target-data is returned unchanged and no error is raised. If parent-xpath does not match a sequence of element nodes in particular, if parent-xpath matches one or more attribute or text nodes , then an error is raised.

The at-sign is not part of the actual attribute name, but serves in the argument to indicate that child-name refers to an attribute. If one or more elements are being inserted, then this is of datatype XMLType , and it contains element nodes. Each of the top-level element nodes in child-data must have the same name tag as child-name or else an error is raised.

If an attribute of the same name already exists at the insertion location, then an error is raised. XML data child-data is inserted as one or more child elements, or a single child attribute, under each of the parent elements located at parent-xpath ; the result is returned. If child-name is NULL , then an error is raised. If child-name names an element, then no insertion is done; target-data is returned unchanged. If target-data is XML schema-based , then the schema is consulted to determine the insertion positions.

For example, if the schema constrains child elements named child-name to be the first child elements of a parent-xpath , then the insertion takes this into account.

Similarly, if the child-name or child-data argument is inappropriate for an associated schema, then an error is raised. If the parent element does not yet have a child corresponding in name and kind to child-name and if such a child is permitted by the associated XML schema, if any , then child-data is inserted as new child elements, or a new attribute value, named child-name.

If the parent element already has a child attribute named child-name without the at-sign , then an error is raised. If the parent element already has a child element named child-name and if more than one child element is permitted by the associated XML schema, if any , then child-data is inserted so that its elements become the last child elements named child-name.

If XML data to be updated is XML schema-based and it refers to a namespace, then the data to be inserted must also refer to the same namespace; otherwise, an error will be raised because the inserted data does not conform to the XML schema. For example, if the data in Example used the namespace films. Example Inserting an Element that Uses a Namespace.