Enum QueryOperation 

pub enum QueryOperation {
    Scan {
        table: String,
        estimated_rows: usize,
    },
    Filter {
        predicate: String,
        selectivity: f64,
    },
    Join {
        left_cost: f64,
        right_cost: f64,
        join_type: JoinType,
    },
    Aggregate {
        group_by: Vec<String>,
    },
    Sort {
        columns: Vec<String>,
    },
    Limit {
        count: usize,
    },
    Project {
        columns: Vec<String>,
    },
}

A single logical query operation. Each variant carries the data the optimizer needs to estimate cost, reorder steps, and select join strategies.

Variants

Scan

Full table scan; estimated_rows is the table’s row count.

Fields

table: String

estimated_rows: usize

Filter

Predicate filter; selectivity (0.0–1.0) is the fraction of rows that pass.

Fields

predicate: String

selectivity: f64

Join

Join of two inputs; left_cost/right_cost are estimated row counts of the left and right inputs. The optimizer may override join_type.

Fields

left_cost: f64

right_cost: f64

join_type: JoinType

Aggregate

Aggregation; group_by lists the grouping columns.

Fields

group_by: Vec<String>

Sort

Sort by the given columns.

Fields

columns: Vec<String>

Limit

Limit to at most count rows.

Fields

count: usize

Project

Column projection.

Fields

columns: Vec<String>

Trait Implementations

impl Clone for QueryOperation

fn clone(&self) -> QueryOperation

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for QueryOperation

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

Formats the value using the given formatter.

impl PartialEq for QueryOperation

fn eq(&self, other: &QueryOperation) -> 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 StructuralPartialEq for QueryOperation