This page contains a glossary of a few common terms used in DuckDB.

Terms

In-Process Database Management System

The DBMS runs in the client application's process instead of running as a separate process, which is common in the traditional client–server setup. An alternative term is embeddable database management system. In general, the term “embedded database management system” should be avoided, as it can be confused with DBMSs targeting embedded systems (which run on e.g., microcontrollers).

Replacement Scan

In DuckDB, replacement scans are used when a table name used by a query does not exist in the catalog. These scans can substitute another data source instead of the table. Using replacement scans allows DuckDB to, e.g., seamlessly read Pandas DataFrames or read input data from remote sources without explicitly invoking the functions that perform this (e.g., reading Parquet files from https). For details, see the C API - Replacement Scans page.

Extension

DuckDB has a flexible extension mechanism that allows for dynamically loading extensions. These may extend DuckDB's functionality by providing support for additional file formats, introducing new types, and domain-specific functionality. For details, see the Extensions page.

Platform

The platform is a combination of the operating system (e.g., Linux, macOS, Windows), system architecture (e.g., AMD64, ARM64), and, optionally, the compiler used (e.g., GCC4). Platforms are used to distributed DuckDB binaries and extension packages.