Reference

RDF::Query::Compiler::SQL(3pm)

Compile a SPARQL query directly to SQL.

NAME

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

VERSION

This document describes RDF::Query::Compiler::SQL version 2.919.

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 <[email protected]>

History