Table of Contents

Query

In one line: a question you ask of your data — by component shape, field value, or geometry — evaluated against a transaction's snapshot.

A query starts from tx.Query<Unit>(), which returns a builder you refine with chainable filters: With/Without/Enabled (component shape), Where (any predicate, broad scan) vs WhereField (an indexed field, targeted scan), and spatial predicates (WhereNearby/WhereInAABB/WhereRay). Nothing runs until a terminal: Execute (materialise ids), Count, Any, or foreach.

The engine picks the scan for you — targeted (index-driven, cheap as the archetype grows), spatial, or broad (linear) — guided by lightweight statistics it maintains. Keep a query result current over time by turning it into a view.

How it relates

  • Archetype — a query is typed on one: tx.Query<Unit>().
  • Index — a WhereField on an indexed field drives the fast path.
  • Spatial index — geometric predicates run off the spatial structure.
  • View — a query kept current, with deltas.
  • Snapshot isolation — what a one-shot query sees.

In the API

Learn & use

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