Triples

Triples — Triple pattern or RDF triple.

Synopsis

                    rasqal_triple;
rasqal_triple *     rasqal_new_triple                   (rasqal_literal *subject,
                                                         rasqal_literal *predicate,
                                                         rasqal_literal *object);
rasqal_triple *     rasqal_new_triple_from_triple       (rasqal_triple *t);
void                rasqal_free_triple                  (rasqal_triple *t);
rasqal_literal *    rasqal_triple_get_origin            (rasqal_triple *t);
enum                rasqal_triple_parts;
int                 rasqal_triple_print                 (rasqal_triple *t,
                                                         FILE *fh);
void                rasqal_triple_set_origin            (rasqal_triple *t,
                                                         rasqal_literal *l);

Description

An object for a triple pattern or an RDF triple in a query. It contains the three parts of an RDF triple - subject, predicate, object as well as origin for matching triples in some graph (such as with the SPARQL GRAPH).

Details

rasqal_triple

typedef struct {
  rasqal_literal* subject;
  rasqal_literal* predicate;
  rasqal_literal* object;
  rasqal_literal* origin;
  unsigned int flags;
} rasqal_triple;

A triple pattern or RDF triple.

This is used as a triple pattern in queries and an RDF triple when generating RDF triples such as with SPARQL CONSTRUCT.

rasqal_literal *`subject`;	Triple subject.
rasqal_literal *`predicate`;	Triple predicate.
rasqal_literal *`object`;	Triple object.
rasqal_literal *`origin`;	Triple origin.
unsigned int `flags`;	Or of enum rasqal_triple_flags bits.

rasqal_new_triple ()

rasqal_triple *     rasqal_new_triple                   (rasqal_literal *subject,
                                                         rasqal_literal *predicate,
                                                         rasqal_literal *object);

Constructor - create a new rasqal_triple triple or triple pattern. Takes ownership of the literals passed in.

The triple origin can be set with rasqal_triple_set_origin().

`subject` :	Triple subject.
`predicate` :	Triple predicate.
`object` :	Triple object.
Returns :	a new rasqal_triple or NULL on failure.

rasqal_new_triple_from_triple ()

rasqal_triple *     rasqal_new_triple_from_triple       (rasqal_triple *t);

Copy constructor - create a new rasqal_triple from an existing one.

`t` :	Triple to copy.
Returns :	a new rasqal_triple or NULL on failure.

rasqal_free_triple ()

void                rasqal_free_triple                  (rasqal_triple *t);

Destructor - destroy a rasqal_triple object.

t :

rasqal_triple object.

rasqal_triple_get_origin ()

rasqal_literal *    rasqal_triple_get_origin            (rasqal_triple *t);

Get the origin field of a rasqal_triple.

`t` :	The triple object.
Returns :	The triple origin or NULL.

enum rasqal_triple_parts

typedef enum {
  RASQAL_TRIPLE_NONE     = 0,
  RASQAL_TRIPLE_SUBJECT  = 1,
  RASQAL_TRIPLE_PREDICATE= 2,
  RASQAL_TRIPLE_OBJECT   = 4,
  RASQAL_TRIPLE_ORIGIN   = 8,
  RASQAL_TRIPLE_GRAPH    = RASQAL_TRIPLE_ORIGIN,
  RASQAL_TRIPLE_SPO      = RASQAL_TRIPLE_SUBJECT | RASQAL_TRIPLE_PREDICATE | RASQAL_TRIPLE_OBJECT,
  RASQAL_TRIPLE_SPOG     = RASQAL_TRIPLE_SPO | RASQAL_TRIPLE_GRAPH
} rasqal_triple_parts;

Flags for parts of a triple.

`RASQAL_TRIPLE_NONE`	no parts
`RASQAL_TRIPLE_SUBJECT`	Subject present in a triple.
`RASQAL_TRIPLE_PREDICATE`	Predicate present in a triple.
`RASQAL_TRIPLE_OBJECT`	Object present in a triple.
`RASQAL_TRIPLE_ORIGIN`	Origin/graph present in a triple.
`RASQAL_TRIPLE_GRAPH`	Alias for RASQAL_TRIPLE_ORIGIN
`RASQAL_TRIPLE_SPO`	Subject, Predicate and Object present in a triple.
`RASQAL_TRIPLE_SPOG`	Subject, Predicate, Object, Graph present in a triple.

rasqal_triple_print ()

int                 rasqal_triple_print                 (rasqal_triple *t,
                                                         FILE *fh);

Print a Rasqal triple in a debug format.

The print debug format may change in any release.

`t` :	rasqal_triple object.
`fh` :	The FILE* handle to print to.
Returns :	non-0 on failure

rasqal_triple_set_origin ()

void                rasqal_triple_set_origin            (rasqal_triple *t,
                                                         rasqal_literal *l);

Set the origin field of a rasqal_triple.

`t` :	The triple object.
`l` :	The rasqal_literal object to set as origin.

			Rasqal RDF Query Library Manual
Top \| Description