NAME

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

VERSION

       This document describes RDF::Query::Compiler::SQL version 2.918.

STATUS

       This module's API and functionality should be considered deprecated.  If you need functionality that this
       module provides, please get in touch <http://www.perlrdf.org/>.

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>