#include <DbXml.hpp>
XmlValue getNode(const std::string &nodeHandle, u_int32_t flags = 0)
XmlDocument getNode(
XmlTransaction &txn, const std::string &nodeHandle,
u_int32_t flags = 0)
The XmlContainer::getNode method returns the
XmlValue
of type
representing the specified handle. The handle must represent a node
in a document in the
XmlContainer
. If the document or node has
been removed, the operation may fail.
XmlValue::NODE
Node handles are guaranteed to remain stable in the absence of modifications to a document. If a document is modified, a handle may cease to exist, or may belong to a different node.
If the operation is to be transaction-protected, the
txn parameter is an
XmlTransaction
handle
returned from XmlManager::createTransaction.
The handle representing the node which must have been obtained using XmlValue::getNodeHandle.
This parameter must be set to 0 or one the following values:
DB_READ_UNCOMMITTED
This operation will support degree 1 isolation; that is,
read operations may return data that has been modified
by other transactions but which has not yet been
committed. Silently ignored if the DB_READ_UNCOMMITTED
flag was not specified when the underlying container was
opened.
DB_READ_COMMITTED
This operation will have degree 2 isolation. This provides for cursor stability but not repeatable reads. Data items which have been previously read by this transaction may be deleted or modified by other transactions before this transaction completes.
DB_RMW
Acquire write locks instead of read locks when doing the read, if locking is configured. Setting this flag can eliminate deadlock during a read-modify-write cycle by acquiring the write lock during the read part of the cycle so that another thread of control acquiring a read lock for the same item, in its own read-modify-write cycle, will not result in deadlock.
DBXML_LAZY_DOCS
Retrieve the document lazily. That is, retrieve document content and document metadata only on an as needed basis when reading the document.
The XmlContainer::getNode method may fail
and throw
XmlException
, encapsulating one of the following
non-zero errors:
An error occurred in an underlying Berkeley DB database. The XmlException::getDbErrno method will return the error code for the error.