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Index (secondary)

In one line: mark a component field [Index] and Typhon maintains a sorted B+Tree so it can be looked up directly instead of scanned.

A plain field can only be found by scanning the archetype. [Index] builds and maintains an index behind the scenes; a query that targets that field (WhereField<Team>(t => t.Id == 3)) is served from the index rather than a broad scan, and stays cheap as the archetype grows. [Index] is unique (a duplicate key throws UniqueConstraintViolationException); [Index(AllowMultiple = true)] lets many entities share a value.

You never touch the tree — you declare the index and filter on the field. An IndexRef is the handle when you resolve one directly.

How it relates

  • Component — an index is declared on a component field.
  • Query — a WhereField filter on an indexed field drives a targeted (fast) scan.
  • View — an indexed WhereField predicate backs an incremental live view.
  • Storage mode — index freshness/maintenance timing follows the component's mode.
  • Spatial index — the geometric sibling, for "what's near here?".

In the API

  • IndexRef — the index-resolution handle.
  • [Index] / [Index(AllowMultiple = true)] — the field attributes (declaration-only, not in the API reference).

Learn & use

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