Struct IndexQuery 

pub struct IndexQuery {
    pub constraints: Vec<ConstraintSpec>,
    pub order_by: Vec<OrderSpec>,
    pub usage: Vec<ConstraintUsage>,
    pub index_number: i32,
    pub index_string: String,
    pub ordered: bool,
    pub estimated_cost: f64,
    pub estimated_rows: i64,
}

The question put to a module’s best_index, and the answer written back.

Fields

constraints: Vec<ConstraintSpec>

The constraints the query can offer.

order_by: Vec<OrderSpec>

The ordering the query would like.

usage: Vec<ConstraintUsage>

What the module decided about each constraint, in the same order.

index_number: i32

The plan number the module chose, passed back to filter.

index_string: String

The plan string the module chose, passed back to filter.

ordered: bool

Whether the rows will already be in the requested order.

estimated_cost: f64

What the module thinks the scan will cost.

estimated_rows: i64

How many rows the module thinks it will produce.

Implementations

impl IndexQuery

pub fn new( constraints: Vec<ConstraintSpec>, order_by: Vec<OrderSpec>, ) -> IndexQuery

Returns a question with every answer at its default.

pub fn use_constraint(&mut self, index: usize, omit: bool) -> usize

Marks one constraint as used, taking the next argument position.

pub fn argument_order(&self) -> Vec<usize>

Returns the constraint positions that feed filter, in argument order.

Trait Implementations

impl Clone for IndexQuery

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for IndexQuery

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

Formats the value using the given formatter.

impl PartialEq for IndexQuery

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for IndexQuery