Creating Models › Creating a Physical Model › Indexes › Index Default Values

Index Default Values

When you create an index, the same key designator is assigned to all the columns in the index. For example, if the CUSTOMER entity has two columns designated as AK1, an AK1 index is created and both AK1 columns are selected as the columns for that index. A default name is assigned to the index and default values are assigned to all the physical properties of the new index. The default name for an index is specified by the IndexName macro.

When an index is created, primary and alternate key indexes do not accept duplicate values. These settings can prevent you from storing unnecessary and potentially confusing data, such as saving two rows in the CUSTOMER table for the same customer. You can use the Table Index Editor to change the settings for alternate key indexes (by making them inversion entries) so that you can allow or prevent duplicate values for indexed columns. If you expect duplicate information to appear in an indexed column, you can choose to change these settings.

A foreign key index is automatically created when a foreign key is created through migration. You can create an alternate key or inversion entry index using an existing index as a source. You can also add a column to an index using the Table Column Editor.

When you generate the schema from a model, an index for the primary key (PK) is created, and a separate index for each alternate key (AK), foreign key (IF), and inversion entry (IE) is created.

By default, the name for a new index is based on the table name. If you change the table name, the index name also changes. When you change the index name, you break the association between the index name and the table name.