RDF::Query::Compiler::SQL(3pm)				User Contributed Perl Documentation			    RDF::Query::Compiler::SQL(3pm)

NAME

       RDF::Query::Compiler::SQL - Compile a SPARQL query directly to SQL.

VERSION

       This document describes RDF::Query::Compiler::SQL version 2.908.

METHODS

       "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.

	   %args may contain callback closures for the following keys:

	     '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.

	   %args may contain callback closures for the following keys:

	     'where_hook'
	     'from_hook'

	   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.

       "_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.

       "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.

       "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.

       "get_function ( $uri )"
	   If $uri is associated with a query function, returns a CODE reference to the function. Otherwise returns "undef".

AUTHOR

	Gregory Williams <gwilliams@cpan.org>

perl v5.14.2							    2012-01-31					    RDF::Query::Compiler::SQL(3pm)