Struct Projection 

pub struct Projection { /* private fields */ }

The columns a projected scan returns: intrinsic columns and value fields, in the order the scan yields them, and the projector that reads the fields out of row values.

Implementations

impl Projection

pub fn new() -> Self

An empty projection.

pub fn column(self, column_id: u16) -> Self

Adds a column projected by id alone (see ProjectedField::by_id).

pub fn field(self, field: ProjectedField) -> Self

Adds a declared field.

pub fn projector(self, projector: Arc<dyn ValueProjector>) -> Self

Sets the projector that reads the fields out of row values.

pub fn fields(&self) -> &[ProjectedField]

The projected fields, in output order.

pub fn value_projector(&self) -> Option<&Arc<dyn ValueProjector>>

The projector, when one is set.

Trait Implementations

impl Clone for Projection

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 Projection

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

Formats the value using the given formatter.

impl Default for Projection

fn default() -> Self

Returns the “default value” for a type.

impl From<&Projection> for Projection

fn from(projection: &Self) -> Self

Converts to this type from the input type.

impl From<&Vec<u16>> for Projection

fn from(ids: &Vec<u16>) -> Self

Converts to this type from the input type.

impl<const N: usize> From<&[u16; N]> for Projection

fn from(ids: &[u16; N]) -> Self

Converts to this type from the input type.

impl From<&[u16]> for Projection

fn from(ids: &[u16]) -> Self

Converts to this type from the input type.