Name
xmlview — Returns the xml document corresponding to given XML view
Synopsis
xmlview
(
|
in
view_name
varchar
); |
Description
The function returns the output produced by an XML view as it was a content of some XML document accessed via document() XPath function. The result of the function call may be used as input of some path expression that select interesting parts of the full output of the XML view. The XQuery engine will translate the XPath expression into SQL statement in order to avoid redundant data access and to build whole XML tree.
This function may be used only in the header of FOR operator of XQuery. To specify the list of values of a variable, a path expression may be used that starts with the call of xmlview() function.
Parameters
view_name
The name of xml view
Errors
Table 24.153. Errors signalled by
xmlview
| SQLState | Error Code | Error Text | Description |
|---|---|---|---|
| 37000 | Unknown view name is passed as argument of xmlview() |
Examples
Example 24.637.
The XQUERY expressions below are queries to the following XML view:
create xml view "cat" as
{
"Demo"."demo"."Categories" c as "category" ("CategoryID", "Description" as "description")
{
"Demo"."demo"."Products" p as "product" ("ProductName")
on (p."CategoryID" = c."CategoryID")
}
};
The first query returns all products with the attribute ProductName starting with "L". The second query returns categories with attribute CategoryID less than 10.
for $r in xmlview("cat")//product[@ProductName like "L%"] return $r
for $r in xmlview("cat")/category[@CategoryID<"10"] return $r