Knowledge Discovery 26.2
Knowledge Discovery Expert

# Example: Virtual Databases

A DAH has three child servers:

- server 0 has a database of dog information, called `dogs`.

- server 1 has:

  - a database of cat information, called `cats`.
  - a database of parrot information, called `parrots`.

- server 2 has a database of flower information, called `flowers`.

## Configuration

The following DAH VDB configuration queries all information about pets:

    [VDB0]
    Name=pets
    MapsTo=0:dogs,1:cats,1:parrots
    Type=combinator

In this example, note that:

- You do not have to reference all child servers in the `MapsTo` parameter.

- You can reference the same child server multiple times.

## Query

When DAH receives a query with `DatabaseMatch` set to `pets`, DAH sends:

- the query with `DatabaseMatch` set to `dogs` to server 0.

- the query with `DatabaseMatch` set to `cats+parrots` to server 1.

  TIP: There are other advanced distribution options for VDBs, such as multi-stage querying. For more information, refer to the DAH Reference.

Copyright 2026 Open Text
Version 26.2 | Last updated April 2026

Send documentation feedback

Close

Send documentation feedback

To send feedback using your default email client, open an email window.

Otherwise, send your feedback and the information below to MFI-swpdl.idoldocsfeedback@opentext.com.

We appreciate your feedback!

Product: Knowledge Discovery 26.2

Topic Title: Example: Virtual Databases