QXmlQuery Class Reference
[QtXmlPatterns module]

void QXmlQuery::bindVariable ( const QXmlName & name, const QXmlItem & value )

Binds the variable name to the value so that $name can be used from within the query to refer to the value.

name must not be null. name.isNull() must return false. If name has already been bound by a previous bindVariable() call, its previous binding will be overridden.

If value is null so that value.isNull() returns true, and name already has a binding, the effect is to remove the existing binding for name.

To bind a value of type QString or QUrl, wrap the value in a QVariant such that QXmlItem's QVariant constructor is called.

All strings processed by the query must be valid XQuery strings, which means they must contain only XML 1.0 characters. However, this requirement is not checked. If the query processes an invalid string, the behavior is undefined.

See also QVariant::isValid(), How QVariant maps to XQuery's Data Model, and QXmlItem::isNull().

void QXmlQuery::bindVariable ( const QXmlName & name, QIODevice * device )

Binds the variable name to the device so that $name can be used from within the query to refer to the device. The QIODevice device is exposed to the query as a URI of type xs:anyURI, which can be passed to the fn:doc() function to be read. E.g., this function can be used to pass an XML document in memory to fn:doc.

     QByteArray myDocument;
     QBuffer buffer(&myDocument); // This is a QIODevice.
     buffer.open(QIODevice::ReadOnly);
     QXmlQuery query;
     query.bindVariable("myDocument", &buffer);
     query.setQuery("doc($myDocument)");

The caller must ensure that device has been opened with at least QIODevice::ReadOnly prior to this binding. Otherwise, behavior is undefined.

If the query will access an XML document contained in a QString, use a QBuffer as shown in the following snippet. Suppose myQString contains <document>content</document>

     QBuffer device;
     device.setData(myQString.toUtf8());
     device.open(QIODevice::ReadOnly);

     QXmlQuery query;
     query.setQuery("doc($inputDocument)/query[theDocument]");
     query.bindVariable("inputDocument", &device);

name must not be null. name.isNull() must return false. If name has already been bound, its previous binding will be overridden. The URI that name evaluates to is arbitrary and may change.

If the type of the variable binding changes (e.g., if a previous binding by the same name was a QVariant, or if there was no previous binding), isValid() will return false, and recompilation of the query text is required. To recompile the query, call setQuery(). For this reason, bindVariable() should be called before setQuery(), if possible.

Note: device must not be deleted while this QXmlQuery exists.

void QXmlQuery::bindVariable ( const QXmlName & name, const QXmlQuery & query )

Binds the result of the query query, to a variable by name name.

Evaluation of query will be commenced when this function is called.

If query is invalid, behavior is undefined. query will be copied.

This function was introduced in Qt 4.5.

See also isValid().

void QXmlQuery::bindVariable ( const QString & localName, const QXmlItem & value )

This is an overloaded function.

This function constructs a QXmlName from localName using the query's namespace. The function then behaves as the overloaded function. It is equivalent to the following snippet.

     QXmlNamePool namePool(query.namePool());
     query.bindVariable(QXmlName(namePool, localName), value);

void QXmlQuery::bindVariable ( const QString & localName, QIODevice * device )

This is an overloaded function.

If localName is a valid NCName, this function is equivalent to the following snippet.

     QXmlNamePool namePool(query.namePool());
     query.bindVariable(QXmlName(namePool, localName), device);

A QXmlName is constructed from localName, and is passed to the appropriate overload along with device.

See also QXmlName::isNCName().

void QXmlQuery::bindVariable ( const QString & localName, const QXmlQuery & query )

This is an overloaded function.

Has the same behavior and effects as the function being overloaded, but takes the variable name localName as a QString. query is used as in the overloaded function.

This function was introduced in Qt 4.5.