Enum RelValue 

pub enum RelValue<'a> {
    Row(RowRef<'a>),
    Projection(ProductValue),
    ProjRef(&'a ProductValue),
}

RelValue represents either a reference to a row in a table, a reference to an inserted row, or an ephemeral row constructed during query execution.

A RelValue is the type generated/consumed by queries.

Variants

Row(RowRef<'a>)

A reference to a row in a table.

Projection(ProductValue)

An ephemeral row made during query execution.

ProjRef(&'a ProductValue)

A row coming directly from a collected update.

This is really a row in a table, and not an actual projection. However, for (lifetime) reasons, we cannot (yet) keep it as a RowRef<'_> and must convert that into a ProductValue.

Implementations

impl<'a> RelValue<'a>

pub fn into_product_value(self) -> ProductValue

Converts self into a ProductValue either by reading a value from a table, cloning the reference to a ProductValue, or consuming the owned product.

pub fn into_product_value_cow(self) -> Cow<'a, ProductValue>

Converts self into a Cow<'a, ProductValue> either by reading a value from a table, passing the reference to a ProductValue, or consuming the owned product.

pub fn num_columns(&self) -> usize

Computes the number of columns in this value.

pub fn extend(self, other: RelValue<'a>) -> RelValue<'a>

Extends self with the columns in other.

This will always cause RowRef<'_>s to be read out into ProductValues.

pub fn read_column(&self, col: usize) -> Option<Cow<'_, AlgebraicValue>>

Read the column at index col.

Use read_or_take_column instead if you have ownership of self.

pub fn get(&'a self, col: ColExprRef<'a>) -> Cow<'a, AlgebraicValue>

Returns a column either at the index specified in col, or the column is the value that col holds.

Panics if, for ColExprRef::Col(col), the col is out of bounds of self.

pub fn read_or_take_column(&mut self, col: usize) -> Option<AlgebraicValue>

Reads or takes the column at col. Calling this method consumes the column at col for a RelValue::Projection, so it should not be called again for the same input.

Panics if col is out of bounds of self.

pub fn project_owned(self, cols: &[ColExpr]) -> ProductValue

Turns cols into a product where a value in cols is taken directly from it and indices are taken from self.

Panics on an index that is out of bounds of self.

Trait Implementations

impl<'a> Clone for RelValue<'a>

fn clone(&self) -> RelValue<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Debug for RelValue<'a>

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

Formats the value using the given formatter.

impl<'a> From<Row<'a>> for RelValue<'a>

fn from(value: Row<'a>) -> Self

Converts to this type from the input type.

impl Hash for RelValue<'_>

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

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 RelValue<'_>

fn eq(&self, other: &Self) -> 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<'a> Serialize for RelValue<'a>

fn serialize<S: Serializer>(&self, ser: S) -> Result<S::Ok, S::Error>

Serialize self in the data format of S using the provided serializer.

impl ToBsatn for RelValue<'_>

fn to_bsatn_vec(&self) -> Result<Vec<u8>, BsatnError>

BSATN-encode the row referred to by self into a freshly-allocated Vec<u8>.

fn to_bsatn_extend(&self, buf: &mut Vec<u8>) -> Result<(), BsatnError>

BSATN-encode the row referred to by self into buf, pushing self’s bytes onto the end of buf, similar to Vec::extend.

fn static_bsatn_size(&self) -> Option<u16>

Returns the static size of the type of this object.

impl Eq for RelValue<'_>