addindex

Addindex is a term used in various software libraries to refer to a function or method that creates or registers an index on a dataset, collection, or table. It is not a standardized command, and the exact syntax, capabilities, and side effects depend on the specific library or framework being used. In general, an index is a data structure that maps key values to the locations of the corresponding records, enabling faster lookups, range queries, sorts, and joins.

Purpose and scope

The primary purpose of adding an index is to improve query performance for operations that search, filter, or order by the indexed fields. Indexes can be built on single or multiple fields and may support options such as uniqueness, sparsity, or partial indexing. While they speed up reads, indexes add overhead to write operations and consume storage space, so they require careful design and maintenance.

Typical usage patterns

In many APIs, addindex(target, spec, options) takes a target data structure, a specification of one or more fields with sort directions, and optional settings. Common options include unique to enforce distinct values, background or online building to minimize locking, and a name for the index. Some libraries also provide synonyms such as addIndex, createIndex, or ensureIndex, with behavior that may differ slightly across systems.

Examples and equivalents

In SQL, the equivalent operation is CREATE INDEX, which defines an index on one or more columns. In MongoDB, the closest analogue is createIndex; older drivers used ensureIndex in some contexts. The exact function name addindex is therefore library-specific and not universally standardized.

See also

Index, Database indexing, Create index, Unique constraint, Full-text index.