MultipleDatabases

Database Routing

Kitto allows you to work with more than one databases at a time through the database routing feature. The basic use of this feature is explained here.

Database routing at the View level

Beside linking a model to a particular database, you can do database routing at the DataView level, using exactly the same syntax:

DatabaseRouter: Static
  DatabaseName: Other

This is useful in case you have multiple databases with similar structure and want to define a single model with different views each linked to a different database.

Other uses of database routing

Database routing is enabled in other places, always through the same syntax. These places are:

Config.yaml/AccessControl	For database-based access controllers, defines the database holding the AC data.
Config.yaml/Auth	For database-based authenticators, defines the database holding the auth data (user names and passwords, generally.
DynaList filters in a List controller	You can fetch the list of values for a list filter from a different database if nedded.

Generally, you can use database routing everywhere a database connection is implied.

Advanced: Customizing database routing

All examples of database routing we have seen so far have been using the Static router, but you can create your own router if you have a dynamic rule that matches models to databases (for example, a naming convention). Creating your own router involves looking into the Kitto.DatabaseRouter unit and using the existing Static router as an example. It all boils down to inheriting a new class from TKDatabaseRouter and overriding the InternalGetDatabaseName method to implement said rule. Your new router can have as many parameters as needed. Everything below the DatabaseRouter node is passed to the InternalGetDatabaseName method at run time.

Don't forget to call TKDatabaseRouterRegistry.Instance.RegisterClass in your initialization section (and the symmetrical TKDatabaseRouterRegistry.Instance.UnregisterClass in the finalization section) in order to make your custom database router available to your application.