UPDATEXMLfunction is deprecated. It is still supported for backward compatibility. However, Oracle recommends that you use XQuery Update instead. See Oracle XML DB Developer's Guide for more information.
UPDATEXML takes as arguments an
XMLType instance and an XPath-value pair and returns an
XMLType instance with the updated value. If
XPath_string is an XML element, then the corresponding
value_expr must be an
XMLType instance. If
XPath_string is an attribute or text node, then the
value_expr can be any scalar data type. You can specify an absolute
XPath_string with an initial slash or a relative
XPath_string by omitting the initial slash. If you omit the initial slash, then the context of the relative path defaults to the root node.
The data types of the target of each
XPath_string and its corresponding
value_expr must match. The optional
namespace_string must resolve to a
VARCHAR2 value that specifies a default mapping or namespace mapping for prefixes, which Oracle Database uses when evaluating the XPath expression(s).
If you update an XML element to null, then Oracle removes the attributes and children of the element, and the element becomes empty. If you update the text node of an element to null, Oracle removes the text value of the element, and the element itself remains but is empty.
In most cases, this function materializes an XML document in memory and updates the value. However,
UPDATEXML is optimized for
UPDATE statements on object-relational columns so that the function updates the value directly in the column. This optimization requires the following conditions:
XMLType_instance must be the same as the column in the
XPath_string must resolve to scalar content.
The following example updates to 4 the number of docks in the San Francisco warehouse in the sample schema
OE, which has a
warehouse_spec column of type
SELECT warehouse_name, EXTRACT(warehouse_spec, '/Warehouse/Docks') "Number of Docks" FROM warehouses WHERE warehouse_name = 'San Francisco'; WAREHOUSE_NAME Number of Docks -------------------- -------------------- San Francisco <Docks>1</Docks> UPDATE warehouses SET warehouse_spec = UPDATEXML(warehouse_spec, '/Warehouse/Docks/text()',4) WHERE warehouse_name = 'San Francisco'; 1 row updated. SELECT warehouse_name, EXTRACT(warehouse_spec, '/Warehouse/Docks') "Number of Docks" FROM warehouses WHERE warehouse_name = 'San Francisco'; WAREHOUSE_NAME Number of Docks -------------------- -------------------- San Francisco <Docks>4</Docks>