Struct Mapper 

pub struct Mapper { /* private fields */ }

Maps row changes of bound relations to input-cell edits.

Implementations

impl Mapper

pub fn new(model: &Model, bindings: HashMap<u32, Vec<Binding>>) -> Self

A mapper for model (its items name the dimension values) with bindings per relation oid. Aggregated bindings start with no rows: Mapper::seed them.

pub fn aggregated(&self) -> Vec<(u32, Binding)>

The aggregated bindings, with their relation oids: each needs a Mapper::seed.

pub fn binds(&self, oid: u32) -> bool

Whether relation oid feeds the model.

pub fn unknown( &self, rels: &HashMap<u32, Relation>, txns: &[Txn], ) -> Vec<(CategoryId, String)>

The dimension values in txns’ rows of bound relations (old rows and new, as the loader’s ::text reads them) that have no item yet, sorted. As the loader does, a row’s non-NULL values count even when another of its dimensions is NULL.

pub fn add_item(&mut self, cat: CategoryId, name: &str, id: ItemId)

Add item id, named name, of category cat (minted by the caller).

pub fn seed( &mut self, model: &mut Model, measure: MeasureId, oid: u32, rows: &[FoldRow], snap: Snap, ) -> Result<(), Rebuild>

Load aggregated measure measure’s fold state from the rows of its seed_sql (snap the snapshot they were read with), its value column being of Postgres type oid, and set model‘s cells for it to the folds’. A text min or max keeps no state (its changes rebuild) and leaves the model’s cells as they are.

pub fn map( &mut self, model: &mut Model, rels: &HashMap<u32, Relation>, txns: &[Txn], replay_until: u64, ) -> Result<Vec<Edit>, Rebuild>

Apply the changes of txns (tuples of the relations in rels) to model’s input cells, as the loader would see the rows, and return one edit per cell whose value the batch changed, with its final value (a cell set back to its old value makes none). Changes to relations without a binding are ignored. Transactions that ended at or before replay_until may already be in model (see the module docs). On Err the model’s inputs and this mapper’s folds are half-updated: discard both.

Trait Implementations

impl Clone for Mapper

fn clone(&self) -> Mapper

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Mapper

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

Formats the value using the given formatter.

impl Default for Mapper

fn default() -> Mapper

Returns the “default value” for a type.