Work / complexity as changes need to also be reflected in associated history tables and triggers. (on more base tables) than the traditional trigger based approach.Ī downside to relative to using Change log is that schema changes (like adding a column) can mean more Into the history tables in the background and in batch and that probably means it can generally be used more widely The approach with Oracle Total Recall reduces the impact to response time by processing the copy of data from redo Now also copy data into the history tables. Of storage (history tables taking storage space) and in terms of impact to response time as updates and deletes Into say ElasticSearch and creating appropriate queries to return as of and version type data).Ī downside to relative to using Change log is that it does introduce extra costs to the database in terms This is also possible with Change log but requires more work (loading the change log With it is easy to query and view the data "As of" a given timestamp and view the versions and historicĬhanges for a given bean/row. Although Ebean makes itĮasier to query and generate the appropriate DDL the capturing of changes is a database function and not strictly Is used to update the database all these changes are captured by the database triggers. If other frameworks (not Ebean) or stored procedures or raw JDBC With changes are transactional and have the associated guarantees - changes can't be missed or lost. Postgres extension - arkhipov/temporal_tables.clarkdave blog post - historical-records-with-postgresql.Potentially updates to the associated triggers Schema changes to the "base table" (add column etc) result in mirrored changes to the "history table" and.Triggers are used on update and delete to copy the existing row data from the "base table" to the associated. A view is used to union all combine the "base table" and the "history table" to simplify history queries.Postgres has a timestamp range type so that is preferred to 2 separate columns for the Postgres implementation. 2 extra columns added to the base table and history table for "effective start" and "effective end" timestamp range.The "history" table does not have constraints by default (no primary key, foreign key or indexes).A "history" table created that has the same (or very similar) structure as the "base table".In general the history table approach results in: For example, this approach is already implementedĪs a Postgres extension - arkhipov/temporal_tables. That has been used for some time and not specific to Ebean. This is a common "Temporal database design" approach In (Postgres, MySql) and Ebean generates history tables/triggers/views to support the feature.įor Postgres, MySql and H2 (and in general databases that don't have SQL2011 support built in) Ebean generatesĭDL for History tables and associated triggers and views. The support for this falls into 2 general cases where someĭatabases have SQL2011 support built in (Oracle, DB2, MS SQL Server 2016) or where it is not built Including AS OF SYSTEM TIME and VERSIONS BETWEEN SYSTEM TIME.Įbean has support for this extension to SQL. SQL2011 introduced temporal extensions to SQL Comparison with the approach taken by Hibernate Envers
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