Temporal tables for Sequelize
(aka "Historical records")
What is it?
Temporal tables maintain historical versions of data. Modifying operations (UPDATE, DELETE) on these tables don't cause permanent changes to entries, but create new versions of them. Hence this might be used to:
- log changes (security/auditing)
- undo functionalities
- track interactions (customer support)
Under the hood a history table with the same structure, but without constraints is created.
The normal singular/plural naming scheme in Sequelize is used:
- model name:
modelName + History
- table name:
modelName + Histories
Installation
npm install sequelize-temporal
How to use
1) Import sequelize-temporal
var Sequelize = require('sequelize');
var Temporal = require('sequelize-temporal');
Create a sequelize instance and your models, e.g.
var sequelize = new Sequelize('', '', '', {
dialect: 'sqlite',
storage: __dirname + '/.test.sqlite'
});
2) Add the temporal feature to your models
var User = Temporal(sequelize.define('User'), sequelize);
The output of temporal
is its input model, so assigning it's output to your
Model is not necessary, hence it's just the lazy version of:
var User = sequelize.define('User', {.types.}, {.options.}); // Sequelize Docu
Temporal(User, sequelize);
Options
The default syntax for Temporal
is:
Temporal(model, sequelizeInstance, options)
whereas the options are listed here (with default value).
// runs the insert within the sequelize hook chain, disable
// for increased performance without warranties
blocking: true
Details
@See: https://wiki.postgresql.org/wiki/SQL2011Temporal
History table
History table stores historical versions of rows, which are inserted by triggers on every modifying operation executed on current table. It has the same structure and indexes as current table, but it doesn’t have any constraints. History tables are insert only and creator should prevent other users from executing updates or deletes by correct user rights settings. Otherwise the history can be violated.
Hooks
Triggers for storing old versions of rows to history table are inspired by referential integrity triggers. They are fired for each row before UPDATE and DELETE (within the same transaction)
Notes
If you only use Postgres, you might want to have a look at the Temporal Table extension.
License
The MIT License (MIT)
Copyright (c) 2015 BonaVal
Permission is hereby granted, free of charge, to any person obtaining a copy
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