Enum Relation 

pub enum Relation {
    Join(Join),
    Aggregate(Aggregate),
}

How a field draws on a related table: either folding its rows in as nested documents (Join) or reducing them to a single value (Aggregate).

Variants

Join(Join)

Fold the related rows in as nested documents, projecting fields from each one.

Aggregate(Aggregate)

Reduce the related rows to a single scalar.

Implementations

impl Relation

pub fn table(&self) -> &TableName

pub fn key(&self) -> RelationKey<'_>

The key tying the related rows and the parent row together.

pub fn filters(&self) -> Option<&[Filter]>

Filters narrowing the related rows, if any.

pub fn via(&self) -> &[ViaHop]

The tables between the parent and table, in order from the parent: an aggregate’s via. Empty for a join and a one-hop aggregate. When non-empty, the key ties the related rows to the last hop rather than to the parent.

pub fn on(&self) -> &[ColumnPair]

The relation’s own extra column equalities: local on the table before table (the parent, or the last via hop), related on table.

pub fn parent_on(&self) -> &[ColumnPair]

The pairs whose local column sits on the parent row: the first via hop’s, or the relation’s own when it has no via.

Trait Implementations

impl Clone for Relation

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 Relation

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Relation

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Hash for Relation

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 Serialize for Relation

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

where __S: Serializer,

Serialize this value into the given Serde serializer.