Reading xml using Oracle - oracle

Question

We have to read a xml using pl/sql. The top few lines of the xml are pasted below. In the xml, for one Node,there is one Equipment. For one Equipment, there are multiple Cabinet. For one Cabinet there are multiple Subrack & for one Subrack there are multiple Boards.
We have developed a below query to parse.
Step-1:
create table emp_xml of xmltype xmltype store as securefile binary xml;
Step-2:
insert into emp_xml values (xmltype(bfilename('XML_DIR','ahm_2015_04_01_172428.xml'), nls_charset_id('AL32UTF8') ));
Step-3:
select * from emp_xml;
Step-4:
select x.*
from emp_xml t,
xmltable(xmlnamespaces(default 'http://www.ericsson.com/axe/export/hw'(http :/ /
www.ericsson.com / axe /
export /
hw%27)),
'/NetworkInventory/Node' passing t.object_value columns
SiteName varchar2(10) path '#Name',
SiteType varchar2(10) path '#Type',
BuildingPractice varchar2(10) path
'//Equipment/#BuildingPractice') x;
This query is working perfectly.But when I am trying to fetch the Cabinet or Subrack details, we are getting below error.
ORA-19279: XPTY0004 - XQuery dynamic type mismatch: expected singleton sequence - got multi-item sequence
ORA-06512: at line 33
19279. 00000 - "XQuery dynamic type mismatch: expected singleton sequence - got multi- item sequence"
*Cause: The XQuery sequence passed in had more than one item.
*Action: Correct the XQuery expression to return a single item sequence.
Top Few Line of XML is given below.
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<NetworkInventory xmlns="http://www.ericsson.com/axe/export/hw" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.ericsson.com/axe/export/hw file:/opt/ericsson/nms_smo_srv/etc/export.xsd">
<Description>AXE HARDWARE INVENTORY DATA</Description>
<ExportDateTime Date="2015-04-01" Time="17:24:28"/>
<Node AdjustDate="2015-03-21" FunctionType=" " Name="BSC20" Site=" " Type="AXE" UserLabel="">
<Equipment BuildingPractice="BYB501">
<Cabinet Position="CabNumber=1">
<Subrack Name="FAN-1" Position="X=3,Y=2" Type="CP">
<Board Name=" " SlotPosition="255" Type="CP">
<ProductData FirstOperationDate="2013-11-20" LastChangedDate="2013-11-20" ManufacturedDate=" " ProductName=" " ProductNumber=" " ProductRevision=" " SerialNumber=" " Supplier="Ericsson AB"/>
</Board>
<Board Name=" " SlotPosition="255" Type="CP">
<ProductData FirstOperationDate="2013-11-20" LastChangedDate="2013-11-20" ManufacturedDate=" " ProductName=" " ProductNumber=" " ProductRevision=" " SerialNumber=" " Supplier="Ericsson AB"/>
</Board>
</Subrack>

Answer 1

Because your Cabinet is set not a single iterate.
When you want to present repeating groups in relational format, you have to extract the sequence of items in the main XQuery expression.
Each item is then passed to the COLUMNS clause to be further shredded into columns.

Answer 2

You're trying to expand a construct that's sort of similar to nested tables. Your Equipment node can have multiple Cabinets, so to extract details from those you need to pass those to a second XMLTable:
select x.SiteName, x.SiteType, x.BuildingPractice, y.Position
from emp_xml t
cross join xmltable(
xmlnamespaces(default 'http://www.ericsson.com/axe/export/hw'),
'/NetworkInventory/Node' passing t.object_value columns
SiteName varchar2(10) path '#Name',
SiteType varchar2(10) path '#Type',
BuildingPractice varchar2(10) path 'Equipment/#BuildingPractice',
Equipment XMLType path 'Equipment'
) x
cross join xmltable(
xmlnamespaces(default 'http://www.ericsson.com/axe/export/hw'),
'//Cabinet' passing x.Equipment columns
Position varchar2(15) path '#Position'
) y;
SITENAME SITETYPE BUILDINGPRACTICE POSITION
---------- ---------- ---------------- ---------------
BSC20 AXE BYB501 CabNumber=1
To get the the SubRack data too, you'd need to pass that out to a third level of XMLTable, etc.