Struct QuadPatternNode 

pub struct QuadPatternNode { /* private fields */ }

A logical node that represents a scan of quads matching a pattern.

This node is the main entry point for accessing RDF data in the query plan. It is responsible for retrieving quads from the underlying storage that match the given active_graph and pattern.

Blank Node Matching

The blank_node_mode determines how blank nodes in the pattern are handled. See BlankNodeMatchingMode for more details.

Planning QuadPatternNode

Planning the QuadPatternNode requires users to define a specialized planner for the used storage layer. This is because the planner should consider storage-specific problems like sharing a transaction across multiple scans of the quads table in a single query. The built-in storage layers of RDF Fusion provide examples.

Implementations

impl QuadPatternNode

pub fn new( storage_encoding: QuadStorageEncoding, active_graph: ActiveGraph, graph_variable: Option<Variable>, pattern: TriplePattern, ) -> QuadPatternNode

Creates a new QuadPatternNode.

pub fn new_with_blank_nodes_as_filter( storage_encoding: QuadStorageEncoding, active_graph: ActiveGraph, graph_variable: Option<Variable>, pattern: TriplePattern, ) -> QuadPatternNode

Creates a new QuadPatternNode.

Contrary to Self::new, blank nodes are not treated as a variable. They are used for filtering the quad set.

pub fn new_all_quads( storage_encoding: QuadStorageEncoding, active_graph: ActiveGraph, ) -> QuadPatternNode

Creates a new QuadPatternNode that returns all quads in active_graph using the default quads schema.

pub fn active_graph(&self) -> &ActiveGraph

The active graph to query.

pub fn graph_variable(&self) -> Option<VariableRef<'_>>

The result mode of the QuadPatternNode.

pub fn pattern(&self) -> &TriplePattern

The triple pattern to match.

pub fn blank_node_mode(&self) -> BlankNodeMatchingMode

The blank node matching mode.

Trait Implementations

impl Debug for QuadPatternNode

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Hash for QuadPatternNode

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for QuadPatternNode

fn eq(&self, other: &QuadPatternNode) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for QuadPatternNode

fn partial_cmp(&self, _other: &QuadPatternNode) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl UserDefinedLogicalNodeCore for QuadPatternNode

fn name(&self) -> &str

Return the plan’s name.

fn inputs(&self) -> Vec<&LogicalPlan>

Return the logical plan’s inputs.

fn schema(&self) -> &Arc<DFSchema>

Return the output schema of this logical plan node.

fn expressions(&self) -> Vec<Expr>

Returns all expressions in the current logical plan node. This should not include expressions of any inputs (aka non-recursively). These expressions are used for optimizer passes and rewrites.

fn fmt_for_explain(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Write a single line, human readable string to f for use in explain plan.

fn with_exprs_and_inputs( &self, exprs: Vec<Expr>, inputs: Vec<LogicalPlan>, ) -> Result<QuadPatternNode, DataFusionError>

Create a new UserDefinedLogicalNode with the specified children and expressions. This function is used during optimization when the plan is being rewritten and a new instance of the UserDefinedLogicalNode must be created.

fn check_invariants( &self, _check: InvariantLevel, ) -> Result<(), DataFusionError>

Perform check of invariants for the extension node.

fn prevent_predicate_push_down_columns(&self) -> HashSet<String>

A list of output columns (e.g. the names of columns in self.schema()) for which predicates can not be pushed below this node without changing the output.

fn necessary_children_exprs( &self, _output_columns: &[usize], ) -> Option<Vec<Vec<usize>>>

Returns the necessary input columns for this node required to compute the columns in the output schema

fn supports_limit_pushdown(&self) -> bool

Returns true if a limit can be safely pushed down through this UserDefinedLogicalNode node.

impl Eq for QuadPatternNode

impl StructuralPartialEq for QuadPatternNode