muutostietokantoja

Muutostietokanta, known in English as a change data capture (CDC) database or simply a history table, is a database system designed to store and manage historical versions of data. Instead of overwriting existing records when they are modified, a muutostietokanta creates a new record to represent the change. This preserves the complete history of data evolution, allowing users to track how data has changed over time, when those changes occurred, and by whom.

The primary purpose of a muutostietokanta is to provide an audit trail and enable temporal querying. This means it's possible to reconstruct the state of the data at any specific point in the past. This capability is invaluable for applications requiring regulatory compliance, detailed auditing, or the ability to analyze trends and historical performance. For instance, financial systems might use a muutostietokanta to track every transaction and account modification for auditing purposes.

Implementation of a muutostietokanta can vary. Some systems use dedicated tables to store historical records, often linked to the current data. Others integrate change tracking directly into the database engine itself. The overhead in terms of storage space and potentially query performance is a consideration, but the benefits of having a complete historical record often outweigh these drawbacks for specific use cases. Data retention policies are crucial to manage the growth of the muutostietokanta over time.