Data Graphs

Data Graphs — RDF graph sources for triples.

Synopsis

                    rasqal_data_graph;
rasqal_data_graph * rasqal_new_data_graph_from_data_graph
                                                        (rasqal_data_graph *dg);
rasqal_data_graph * rasqal_new_data_graph_from_iostream (rasqal_world *world,
                                                         raptor_iostream *iostr,
                                                         raptor_uri *base_uri,
                                                         raptor_uri *name_uri,
                                                         unsigned int flags,
                                                         const char *format_type,
                                                         const char *format_name,
                                                         raptor_uri *format_uri);
rasqal_data_graph * rasqal_new_data_graph_from_uri      (rasqal_world *world,
                                                         raptor_uri *uri,
                                                         raptor_uri *name_uri,
                                                         unsigned int flags,
                                                         const char *format_type,
                                                         const char *format_name,
                                                         raptor_uri *format_uri);
void                rasqal_free_data_graph              (rasqal_data_graph *dg);
enum                rasqal_data_graph_flags;
int                 rasqal_data_graph_print             (rasqal_data_graph *dg,
                                                         FILE *fh);

Description

Data graphs are used in the query to describe RDF graphs that can be used to query against. The graphs can be used either with raptor_uri to name the graph, or without a name. The query language determines which graphs are used in the query.

Details

rasqal_data_graph

typedef struct {
  rasqal_world* world;
  raptor_uri* uri;
  raptor_uri* name_uri;
  unsigned int flags;
  char* format_type;
  char* format_name;
  raptor_uri* format_uri;
  raptor_iostream* iostr;
  raptor_uri* base_uri;
  int usage;
} rasqal_data_graph;

A source of RDF data for querying.

If iostr is present, the graph can be constructed by parsing the iostream and using base_uri as a base uri. Otherwise the graph can be constructed from the graph at URI uri.

In either case the name_uri is the graph name as long as flags is RASQAL_DATA_GRAPH_NAMED

rasqal_world *`world`;	rasqal_world object
raptor_uri *`uri`;	source URI
raptor_uri *`name_uri`;	name of graph for `RASQAL_DATA_GRAPH_NAMED`
unsigned int `flags`;	`RASQAL_DATA_GRAPH_NAMED` or `RASQAL_DATA_GRAPH_BACKGROUND`
char *`format_type`;	MIME Type of data format at `uri` (or NULL)
char *`format_name`;	Raptor parser Name of data format at `uri` (or NULL)
raptor_uri *`format_uri`;	URI of data format at `uri` (or NULL)
raptor_iostream *`iostr`;	Raptor iostream for content, overriding `uri` if present (or NULL)
raptor_uri *`base_uri`;	base URI for reading from iostream
int `usage`;	usage count of this object

rasqal_new_data_graph_from_data_graph ()

rasqal_data_graph * rasqal_new_data_graph_from_data_graph
                                                        (rasqal_data_graph *dg);

Copy Constructor - create a new rasqal_data_graph object from an existing rasqal_data_graph object.

`dg` :	rasqal_data_graph object to copy or NULL
Returns :	a new rasqal_data_graph object or NULL if `dg` was NULL.

rasqal_new_data_graph_from_iostream ()

rasqal_data_graph * rasqal_new_data_graph_from_iostream (rasqal_world *world,
                                                         raptor_iostream *iostr,
                                                         raptor_uri *base_uri,
                                                         raptor_uri *name_uri,
                                                         unsigned int flags,
                                                         const char *format_type,
                                                         const char *format_name,
                                                         raptor_uri *format_uri);

Constructor - create a new rasqal_data_graph from iostream content

The name_uri is used when the flags are RASQAL_DATA_GRAPH_NAMED.

The base_uri is used to provide the Raptor parser a base URI. If a base URI is required but none is given, the parsing will fail and the query that uses this data source will fail.

`world` :	rasqal_world object
`iostr` :	source graph format iostream
`base_uri` :	base URI for iostream content
`name_uri` :	name of graph (or NULL)
`flags` :	`RASQAL_DATA_GRAPH_NAMED` or `RASQAL_DATA_GRAPH_BACKGROUND`
`format_type` :	MIME Type of data format at `uri` (or NULL)
`format_name` :	Raptor parser Name of data format at `uri` (or NULL)
`format_uri` :	URI of data format at `uri` (or NULL)
Returns :	a new rasqal_data_graph or NULL on failure.

rasqal_new_data_graph_from_uri ()

rasqal_data_graph * rasqal_new_data_graph_from_uri      (rasqal_world *world,
                                                         raptor_uri *uri,
                                                         raptor_uri *name_uri,
                                                         unsigned int flags,
                                                         const char *format_type,
                                                         const char *format_name,
                                                         raptor_uri *format_uri);

Constructor - create a new rasqal_data_graph.

The name_uri is only used when the flags are RASQAL_DATA_GRAPH_NAMED.

`world` :	rasqal_world object
`uri` :	source URI
`name_uri` :	name of graph (or NULL)
`flags` :	`RASQAL_DATA_GRAPH_NAMED` or `RASQAL_DATA_GRAPH_BACKGROUND`
`format_type` :	MIME Type of data format at `uri` (or NULL)
`format_name` :	Raptor parser Name of data format at `uri` (or NULL)
`format_uri` :	URI of data format at `uri` (or NULL)
Returns :	a new rasqal_data_graph or NULL on failure.

rasqal_free_data_graph ()

void                rasqal_free_data_graph              (rasqal_data_graph *dg);

Destructor - destroy a rasqal_data_graph object.

dg :

rasqal_data_graph object

enum rasqal_data_graph_flags

typedef enum {
  RASQAL_DATA_GRAPH_NONE  = 0,
  RASQAL_DATA_GRAPH_NAMED = 1,
  RASQAL_DATA_GRAPH_BACKGROUND = 2
} rasqal_data_graph_flags;

Flags for the type of rasqal_data_graph.

These are used by rasqal_new_data_graph_from_uri() and rasqal_new_data_graph_from_iostream(). See rasqal_data_graph.

`RASQAL_DATA_GRAPH_NONE`	Internal.
`RASQAL_DATA_GRAPH_NAMED`	Graphs with a source and name.
`RASQAL_DATA_GRAPH_BACKGROUND`	Graphs with a source only.

rasqal_data_graph_print ()

int                 rasqal_data_graph_print             (rasqal_data_graph *dg,
                                                         FILE *fh);

Print a Rasqal data graph in a debug format.

The print debug format may change in any release.

`dg` :	rasqal_data_graph object
`fh` :	the FILE* handle to print to
Returns :	non-0 on failure

			Rasqal RDF Query Library Manual
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