Physical Modeling › Teradata Physical Property Editors › Define Teradata Hash Indexes

Define Teradata Hash Indexes

You can use the Table Hash Index editor to create a set of new hash indexes on an existing table in a Teradata physical model. The hash index provides an index structure that can be hash-distributed to Access Module Processors (AMPs). The index contains a row identifier that provides transparent access to the base table, which improves query performance by covering columns in a query so that the base table does not need to be accessed, or serves as an alternate access method to the base table in a join or retrieval operation.

To add a new Teradata hash index

1. Click Hash Indexes on the Model menu.

   The Table Hash Index Editor opens.

2. Select a hash index and work with the following options:

   Note: Click New on the toolbar to create a new hash index.

   • Table

     Specifies the table you want to create a Hash index for. Select a table from the drop-down list.

   • Name

     Specifies the name of the hash index.

   • Database

     Defines the database or user.

   • Generate

     Generates DDL for this object during Forward Engineering.

3. Complete the following fields on the General tab:
   • Index Members

     The columns for the table that has the index and are key group members appear. You can select any of the columns to be a key group member. The columns can be sorted.

4. Work with the other tabs in the editor to access additional design features, for example:
   • Specify fallback protection, checksum, and order choices on the Options tab
   • Specify ordering options on the Ordering tab
   • Associate permissions with the selected hash index on the Permission tab
5. (Optional) Click the Comment tab and enter any comments you want associated with the hash index.
6. (Optional) Click the UDP tab to work with user-defined properties for the hash index.
7. Click Close.

   The Hash Index editor closes.