RDF::Query::Compiler::SQL - Compile a SPARQL query directly to SQL.
new ( $parse_tree )
Returns a new compiler object.
compile ()
Returns a SQL query string for the specified parse tree.
emit_select
Returns a SQL query string representing the query.
limit_clause
Returns a SQL LIMIT clause, or an empty string if the query does not need limiting.
order_by_clause
Returns a SQL ORDER BY clause, or an empty string if the query does not use ordering.
variable_columns ( $var )
Given a variable name, returns the set of column aliases that store the values for the column (values for Literals, URIs, and Blank Nodes).
add_variable_values_joins
Modifies the query by adding LEFT JOINs to the tables in the database that contain the node values (for literals, resources, and blank nodes).
patterns2sql ( \@triples, \$level, %args )
Builds the SQL query in instance data from the supplied @triples. $level is used as a unique identifier for recursive calls.
@triples
$level
%args may contain callback closures for the following keys:
%args
'where_hook' 'from_hook'
When present, these closures are used to add SQL FROM and WHERE clauses to the query instead of adding them directly to the object's instance data.
expr2sql ( $expression, \$level, %args )
Returns a SQL expression for the supplied query $expression. $level is used as a unique identifier for recursive calls.
$expression
When present, these closures are used to add necessary SQL FROM and WHERE clauses to the query.
_mysql_hash ( $data )
Returns a hash value for the supplied $data string. This value is computed using the same algorithm that Redland's mysql storage backend uses.
$data
_mysql_node_hash ( $node )
Returns a hash value (computed by _mysql_hash for the supplied $node. The hash value is based on the string value of the node and the node type.
_mysql_hash
$node
qualify_uri ( $uri )
Returns a fully qualified URI from the supplied $uri. $uri may already be a qualified URI, or a parse tree for a qualified URI or QName. If $uri is a QName, the namespaces defined in the query parse tree are used to fully qualify.
$uri
add_function ( $uri, $function )
Associates the custom function $function (a CODE reference) with the specified URI, allowing the function to be called by query FILTERs.
$function
get_function ( $uri )
If $uri is associated with a query function, returns a CODE reference to the function. Otherwise returns undef.
undef
Gregory Williams <gwilliams@cpan.org>
To install RDF::Query, copy and paste the appropriate command in to your terminal.
cpanm
cpanm RDF::Query
CPAN shell
perl -MCPAN -e shell install RDF::Query
For more information on module installation, please visit the detailed CPAN module installation guide.