deletion

Deletion is the act of removing an element from a set, structure, or system. In information technology, deletion refers to removing data, files, or records from storage or memory. Deletion can be implemented as a hard delete, which permanently erases data, or a soft delete (logical delete or tombstone), which marks data as deleted without erasing it, allowing recovery or auditing. In databases, SQL supports hard deletes with DELETE statements; TRUNCATE removes all rows quickly; soft deletes use a deletion flag or a separate archive table to preserve history. File systems may move deleted items to a recycle bin or trash, or remove them immediately depending on configuration. In version control, deleting a file is represented as a change that can be committed; history remains, enabling rollback.

In biology, deletion is a type of structural variation where a portion of a chromosome is missing. Deletions can be terminal (loss at chromosome end) or interstitial; they may cause developmental disorders or predispose to disease, depending on the genes affected. In linguistics, deletion refers to the omission of sounds or letters in speech or writing, often governed by phonological rules or orthographic simplification.

Ethical and practical considerations include data privacy, legal retention requirements, backup and disaster recovery, and the possibility of accidental deletion. Organizations frequently implement deletion policies, versioning, and audit trails to mitigate risk.