Chapter 14. Web services for DB2 Cube Views 619
Let us consider an XML document that describes a Library System:
<LIBRARY>
<BOOK ID=”B1.1”>
<TITLE>xml</TITLE>
<COPIES>5</COPIES>
</BOOK>
<BOOK ID=”B2.1”>
<TITLE>WebSphere</TITLE>
<COPIES>10</COPIES>
</BOOK>
<BOOK ID=”B3.2”>
<TITLE>great novel</TITLE>
<COPIES>10</COPIES>
</BOOK>
<BOOK ID=”B5.5”>
<TITLE>good story</TITLE>
<COPIES>10</COPIES>
</BOOK>
</LIBRARY>
The path /child::book/child::copies selects all copies element children of book
which are defined under the document’s root. The above path can also be written
as /library/book/copies.
The XPath location step makes the selection of document part based on the
basis and the predicate. The basis performs a selection based on Axis Name
and Node Test. Then the predicate performs additional selections based on the
outcome of the selection from the basis. A simple example of this is as follows:
The path /library/book[1] selects the first book element under library.
14.3 Architecture of Web services for DB2 Cube Views
Figure 14-2 sketches the architecture of Web services for DB2 Cube Views.
The OLAP service provider may be registered in a UDDI registry for service
requestors or clients to find and discover Web services to retrieve meta-data, to
execute slice and dice queries, and to retrieve member data.
OLAP Web services client can discover OLAP providers in UDDI registries,
access the provider through the Web services to retrieve XML descriptions of
cubes and execute slice and dice queries on the cubes.
A client application composes a SOAP request envelop containing the input
parameter values and sends it through SOAP and HTTP to the OLAP provider.

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