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d_Extent< T > Class Template Reference

#include <d_Extent.h>

List of all members.

Public Methods
	d_Extent (const d_Database *iDb, d_Boolean iSubClasses=d_True)
	~d_Extent ()
unsigned long	cardinality () const
d_Boolean	is_empty () const
d_Boolean	allows_duplicates () const
d_Boolean	is_ordered () const
d_Iterator< d_Ref< T > >	create_iterator ()
d_Iterator< d_Ref< T > >	begin ()
d_Iterator< d_Ref< T > >	end ()
d_Ref< T >	select_element (const char *iTextQuery) const
d_Iterator< d_Ref< T > >	select (const char *iTextQuery)
void	deleteObjects (const char *iTextQuery)
unsigned long	count (const char *iTextQuery)
int	query (d_Collection< d_Ref< T > > &iColl, const char *iTextQuery) const
d_Boolean	exists_element (const char *iTextQuery) const
void	setQueryEngine (const char *iQueryEngineName)
Protected Methods
	d_Extent (const d_Extent< T > &iSource)
d_Extent< T > &	operator= (const d_Extent< T > &iSource)

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Detailed Description

template<class T>
class d_Extent< T >

The class Extent is a virtual collection of all objects of a class updated automatically by the Orient engine.

QUERIES: Making a query on an Extent means to query all the objects of a class.

LOCATION: d_Extent.h

USAGE: d_Extent< <pers-class-name> > <variable-name>;

Where:

<pers-class-name>: persistent class to use <variable-name>: is the name of d_Extent object

EXAMPLES: d_Ref<Customer> objCustomer; d_Iterator< d_Ref<Customer> > itCustomer; d_Extent<Customer> customers( &db );

itCustomer = customers.select( "Customer.code = 1" );

while( itCustomer.next( objCustomer ) ) { * DISPLAY OBJECT printf( "......: d", objCustomer->code ); printf( "......: s", objCustomer->name.c_str() ); printf( "...: s", objCustomer->surname.c_str() ); printf( ".......: d", objCustomer->age ); printf( ".....: s", objCustomer->notes.c_str() ); }

SEE ALSO: d_Iterator

ODMG: Compliant

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Constructor & Destructor Documentation

template<class T> d_Extent< T >::d_Extent (  const d_Database *    iDb, d_Boolean    iSubClasses = d_True )

Create an d_Extent object. Creates an extent for class specified as template argument (<> bracets) of database . Parameter is not used but available for ODMG compatibility. ODMG : Compliant

template<class T> d_Extent< T >::~d_Extent (    )

Destructor. ODMG : Compliant

template<class T> d_Extent< T >::d_Extent (  const d_Extent< T > &    iSource )  [protected]

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Member Function Documentation

template<class T> d_Boolean d_Extent< T >::allows_duplicates (    )  const [inline]

Returns always false. It's maintained for compatibility with collection classes. ODMG : Compliant

template<class T> d_Iterator< d_Ref<T> > d_Extent< T >::begin (    )

Creates an iterator that points to the first element of extent and returns it. It works like create_iterator() member and is maintained for compatibility with C++ STL containers. SEE ALSO: d_Iterator, create_iterator() ODMG : Compliant

template<class T> unsigned long d_Extent< T >::cardinality (    )  const

Returns total number of object in the extent. This is equal to the total of objects present in the database for that class. ODMG : Compliant

template<class T> unsigned long d_Extent< T >::count (  const char *    iTextQuery )

Counts the number of objects that matches the query predicate. SEE ALSO: select(), cardinality() ODMG : Compliant

template<class T> d_Iterator< d_Ref<T> > d_Extent< T >::create_iterator (    )

Creates an iterator that points to the first element of extent and returns it. SEE ALSO: d_Iterator, begin() ODMG : Compliant

template<class T> void d_Extent< T >::deleteObjects (  const char *    iTextQuery )

Delete objects that satisfy query predicate. is the text of query to execute. SEE ALSO: select() ODMG : Extension

template<class T> d_Iterator< d_Ref<T> > d_Extent< T >::end (    )

Creates an iterator that points to the last element of extent and returns it. Is maintained for compatibility with C++ STL containers. SEE ALSO: d_Iterator, begin() ODMG : Compliant

template<class T> d_Boolean d_Extent< T >::exists_element (  const char *    iTextQuery )  const

Returns true if there is at least one object that matches the query predicate. SEE ALSO: select_element(), select() ODMG : Compliant

template<class T> d_Boolean d_Extent< T >::is_empty (    )  const [inline]

Returns true if the extent doesn't contain objects. ODMG : Compliant

template<class T> d_Boolean d_Extent< T >::is_ordered (    )  const [inline]

Returns always false. It's maintained for compatibility with collection classes. ODMG : Compliant

template<class T> d_Extent<T>& d_Extent< T >::operator= (  const d_Extent< T > &    iSource )  [protected]

template<class T> int d_Extent< T >::query (  d_Collection< d_Ref< T > > &    iColl, const char *    iTextQuery )  const

SEE ALSO: d_Iterator, d_Ref, select_element() ODMG : Compliant

template<class T> d_Iterator< d_Ref<T> > d_Extent< T >::select (  const char *    iTextQuery )

Makes a query on the extent. is the text of query to execute. It returns an iterator that point to the first object that matches the query predicate. To browse the result set use d_Iterator object. SEE ALSO: d_Iterator, d_Ref, select_element() ODMG : Compliant

template<class T> d_Ref<T> d_Extent< T >::select_element (  const char *    iTextQuery )  const

Makes a query on the extent. is the text of query to execute. It returns a reference to the object that matches the query predicate. If more than one object matches the query, then only the first one object scanned is returned. For best performance use this method instead of general select() method when the field of research is unique and doesn't contain duplicates. In this way the research will stop after the first, and unique, match. SEE ALSO: d_Ref, select() ODMG : Compliant

template<class T> void d_Extent< T >::setQueryEngine (  const char *    iQueryEngineName )

Set query language engine. This allow the user to change the language for query at run-time just calling this method. Query engine must be previously registered in the oQueryEngineManager object taken by oQueryEngineManager::getInstance() method. SEE ALSO: oQueryEngineManager ODMG : Extension

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The documentation for this class was generated from the following file:

• d_Extent.h

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