Column-Oriented Database Management System

A column-oriented database management system stores each column of a table contiguously on disk or in memory, rather than storing each row together the way a conventional relational engine does by default. A query that touches only a few columns out of a wide table then has to scan far less data, and storing like values together lets the system compress each column more effectively, which makes this layout well suited to analytical and reporting workloads that aggregate over many rows but comparatively few columns at a time. The trade-off is that reading or writing one complete record becomes more costly than in a row-oriented design, so column-oriented systems are generally favored for read-heavy analytics rather than for high-frequency single-record transactional updates.