Non Clustered Primary Keys

When you create a Primary Key in some DBMSs (such as SQL Server or ASA), it is automatically created with the Is Clustered property set to True. Therefore when you model a Primary Key in an Enterprise Architect data model, the same behavior occurs.

Clustered indexes provide improved performance for accessing the column(s) involved, by physically organizing the data by those columns. There can be only one clustered index per Table.

In some situations, you might be more interested in the performance of columns other than the ones assigned to the Primary Key, and therefore you would need to change the default assignment so that the Primary Key is not clustered.

Access Tools | Database Builder | Click on Table name > Constraints       or

In diagram or Project Browser | Right-click on Table | Features & Properties | Operations > Constraints     or

In diagram or Project Browser | Click on Table: F10

Define Primary Key as non-clustered

Subsequently, you can model an index for the same Table as clustered.



See also


Highlight the existing Primary Key constraint.

The Primary Key properties display in the Property panel.


For the Is Clustered property, in the 'Value' field click on the drop-down arrow and change the value to False.

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