Clusters

Clusters are the schema objects that contain data of one or more tables, that are physically stored together, when tables share common columns and are often used together.

Oracle have two types of clusters - index and hash clusters. In index clusters table rows, that have the same values of the cluster key columns, are stored together. Cluster index must be created for index cluster. It always contains all the cluster columns. In hash clusters table rows, that have the same result of applying hash function to the cluster key value, are stored together.

dbForge Studio allows you to create and edit both types of clusters.

Creating and Editing a Cluster

To create a cluster

  1. Click the New Database Object button on the Standard toolbar.
  2. Select the Cluster type in the dialog box.
  3. Input the cluster name. It is not recommended that a table and a cluster have the same name.
  4. Click the Create button. If specified name is unique, the cluster editor document will appear.
  5. Add required cluster key columns to the cluster.
  6. Optionally, you can alter the name or change schema (owner).
  7. Switch to the Advanced tab, and set cluster type, size, and other parameters.
  8. For index clusters you can optionally click the Edit button, and edit a cluster index name, and storage parameters. It includes all the cluster column, and its column list can not be changed.
  9. Optionally, you can switch to the Storage tab and set cluster storage parameters.
  10. Save the document.

To edit a cluster

  1. In the Database Explorer window, expand the Clusters folder.
  2. Right-click a required cluster, and then click Edit Cluster on the shortcut menu.

To delete a cluster

  1. In the Database Explorer window, expand the Clusters folder.
  2. Right-click a required cluster, and then click Delete on the shortcut menu.