Struct expr::RowSetFinishing

pub struct RowSetFinishing {
    pub order_by: Vec<ColumnOrder>,
    pub limit: Option<usize>,
    pub offset: usize,
    pub project: Vec<usize>,
}

Instructions for finishing the result of a query.

The primary reason for the existence of this structure and attendant code is that SQL’s ORDER BY requires sorting rows (as already implied by the keywords), whereas much of the rest of SQL is defined in terms of unordered multisets. But as it turns out, the same idea can be used to optimize trivial peeks.

Fields

order_by: Vec<ColumnOrder>

Order rows by the given columns.

limit: Option<usize>

Include only as many rows (after offset).

offset: usize

Omit as many rows.

project: Vec<usize>

Include only given columns.

Implementations

impl RowSetFinishing

pub fn is_trivial(&self, arity: usize) -> bool

True if the finishing does nothing to any result set.

pub fn finish(&self, rows: &mut Vec<Row>)

Applies finishing actions to a row set.

Trait Implementations

impl Clone for RowSetFinishing

fn clone(&self) -> RowSetFinishing

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for RowSetFinishing

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for RowSetFinishing

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error> where
    __D: Deserializer<'de>, 

Deserialize this value from the given Serde deserializer.

impl PartialEq<RowSetFinishing> for RowSetFinishing

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl Serialize for RowSetFinishing

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error> where
    __S: Serializer, 

Serialize this value into the given Serde serializer.

impl Eq for RowSetFinishing

impl StructuralEq for RowSetFinishing

impl StructuralPartialEq for RowSetFinishing