query

query

Functions

Types and Values

Description

Functions

librdf_query_register_factory ()

void
librdf_query_register_factory (librdf_world *world,
                               const char *name,
                               const unsigned char *uri_string,
                               void (*factory) (librdf_query_factory*));

Register a query factory.

Parameters

world

redland world object

 

name

the query language name

 

uri_string

the query language URI string (or NULL if none)

 

factory

pointer to function to call to register the factory

 

librdf_query_language_get_description ()

const raptor_syntax_description *
librdf_query_language_get_description (librdf_world *world,
                                       unsigned int counter);

Get a query language syntax description.

Parameters

world

librdf_world

 

counter

index into the list of query language syntaxes

 

Returns

description or NULL if counter is out of range


librdf_query_languages_enumerate ()

int
librdf_query_languages_enumerate (librdf_world *world,
                                  const unsigned int counter,
                                  const char **name,
                                  const unsigned char **uri_string);

librdf_query_languages_enumerate is deprecated and should not be used in newly-written code.

Get information on query language syntaxes.

All returned strings are shared and must be copied if needed to be used dynamically.

deprecated : use librdf_query_language_get_description() to return more information in a static structure.

Parameters

world

librdf_world

 

counter

index into the list of query language syntaxes

 

name

pointer to store the name of the query language syntax (or NULL)

 

uri_string

pointer to store query language syntax URI string (or NULL)

 

Returns

non 0 on failure of if counter is out of range


librdf_new_query ()

librdf_query *
librdf_new_query (librdf_world *world,
                  const char *name,
                  librdf_uri *uri,
                  const unsigned char *query_string,
                  librdf_uri *base_uri);

Constructor - create a new librdf_query object.

Parameters

world

redland world object

 

name

the name identifying the query language

 

uri

the URI identifying the query language (or NULL)

 

query_string

the query string

 

base_uri

the base URI of the query string (or NULL)

 

Returns

a new librdf_query object or NULL on failure


librdf_new_query_from_query ()

librdf_query *
librdf_new_query_from_query (librdf_query *old_query);

Copy constructor - create a new librdf_query object from an existing one

Should create a new query in the same context as the existing one as appropriate.

Parameters

old_query

the existing query librdf_query to use

 

Returns

a new librdf_query object or NULL on failure


librdf_new_query_from_factory ()

librdf_query *
librdf_new_query_from_factory (librdf_world *world,
                               librdf_query_factory *factory,
                               const char *name,
                               librdf_uri *uri,
                               const unsigned char *query_string,
                               librdf_uri *base_uri);

Constructor - create a new librdf_query object.

Parameters

world

redland world object

 

factory

the factory to use to construct the query

 

name

query language name

 

uri

query language URI (or NULL)

 

query_string

the query string

 

base_uri

base URI of the query string (or NULL)

 

Returns

a new librdf_query object or NULL on failure


librdf_free_query ()

void
librdf_free_query (librdf_query *query);

Destructor - destroy a librdf_query object.

Parameters

query

librdf_query object

 

librdf_query_execute ()

librdf_query_results *
librdf_query_execute (librdf_query *query,
                      librdf_model *model);

Run the query on a model.

Runs the query against the (previously registered) model and returns a librdf_query_results for the result objects.

Parameters

query

librdf_query object

 

model

model to operate query on

 

Returns

librdf_query_results or NULL on failure


librdf_query_get_limit ()

int
librdf_query_get_limit (librdf_query *query);

Get the query-specified limit on results.

This is the limit given in the query on the number of results allowed.

Parameters

query

librdf_query query object

 

Returns

integer >=0 if a limit is given, otherwise <0


librdf_query_set_limit ()

int
librdf_query_set_limit (librdf_query *query,
                        int limit);

Set the query-specified limit on results.

This is the limit given in the query on the number of results allowed.

Parameters

query

librdf_query query object

 

limit

the limit on results, >=0 to set a limit, <0 to have no limit

 

Returns

non-0 on failure


librdf_query_get_offset ()

int
librdf_query_get_offset (librdf_query *query);

Get the query-specified offset on results.

This is the offset given in the query on the number of results allowed.

Parameters

query

librdf_query query object

 

Returns

integer >=0 if a offset is given, otherwise <0


librdf_query_set_offset ()

int
librdf_query_set_offset (librdf_query *query,
                         int offset);

Set the query-specified offset on results.

This is the offset given in the query on the number of results allowed.

Parameters

query

librdf_query query object

 

offset

offset for results, >=0 to set an offset, <0 to have no offset

 

Returns

non-0 on failure

Types and Values

librdf_query

typedef struct librdf_query_s librdf_query;

Redland query class.


librdf_query_factory

typedef struct librdf_query_factory_s librdf_query_factory;

Redland query factory class.