Scan

Noun · Development

Definitions

  1. An operation that reads through data sequentially. In databases, a full table scan examines every row (the fallback when no index applies); an index scan traverses index entries. In functional programming, scan (or scanLeft) is a higher-order function that produces a sequence of accumulated intermediate results, like a running total.

    In plain English: Reading through data one item at a time from start to finish, often used when there's no shortcut like an index to jump to the right spot.

    Example: "The query plan shows a sequential scan on a 50-million-row table — we need a composite index on (tenant_id, created_at) to avoid that."

Related Terms