Glossary

Offset pagination — Addressing a page by a 1-based page number and a limit (rows per page). Simple, supports jump-to-page and a total count. See pagination models.

Keyset / cursor pagination — Addressing a page by the ordering values of the last row seen, carried as an opaque cursor. Stable under writes and fast at depth. See pagination models.

Cursor — An opaque, URL-safe string encoding the ordering values of a boundary row. Typed and deterministic, so it round-trips across languages. See cursors.

Spec — A small declarative description of an operation: FilterSpec, SortSpec, or SearchSpec. A dataclass in Python, a plain object in TypeScript; both generated from one schema.

Operator — One of the 20 filter comparisons (eq, gte, contains, between, in, regex, …), expressed as a plain string. See filtering.

Filter group — A nested boolean tree built with And() / Or(), up to 5 levels deep. See filtering.

Dotted field path — A "a.b.c" path that resolves through nested maps to reach a value on each item (e.g. "address.city").

Null placement — Where missing / null values sort, set per key with nulls: "first" | "last", independent of direction. See sorting.

Stable sort — A sort in which items that compare equal keep their original relative order — the basis for predictable multi-key sorting.

Token matching — The default search mode: the query is split into tokens, and an item matches only when every token is found in a searched field. See search.

Trigram — An overlapping 3-character slice of a string (the PostgreSQL pg_trgm model), used to score fuzzy similarity. See search.

Fuzzy search — Typo-tolerant matching via trigram similarity (fuzzy: "fuzzy" or "token_sort"), scored 0–100 against a threshold.

Adapter — The thin, per-language layer that maps host objects / ORM rows to the plain data the core understands and selects results by index. The ORM lives here, never in the core. See architecture.

Marshalling — Converting host data into the core's Value model to cross the FFI boundary. The cost the engine is designed to minimize — see architecture.

Value — The small JSON-like enum the core speaks (Null | Bool | Int | Float | Str | List | Map, plus typed scalars). Nothing host-specific crosses the boundary. See Rust design.

Index-based return — filter / sort / search return a list of indices; the adapter selects your original objects, so rows are never copied through the core.

Columnar fast path — A dense, typed projection (Columns) built once for a resident Dataset, accelerating the filter and sort stages. See performance.

Dataset (resident) — An in-memory dataset marshalled into the core once, then queried many times. Build once, query many. See Python / TypeScript.

Parity — The guarantee that every language package returns identical results and byte-identical cursors, pinned by a golden fixture in CI. See parity.

MAX_LIMIT — The shared maximum page size (a DoS guard), defined once in the core and exposed by every package.