Column Denormalization

Column denormalization consists in replicating columns from one table to another to reduce the number of joins needed for frequently called queries. Though it can provide improved performance, column denormalization requires more maintenance and disk space as the data in the replicated column is stored twice.

1. Select Tools > Denormalization > Column Denormalization, or right-click the table to which you want to replicate columns and select Column Denormalization to open the Column Denormalization Wizard.
2. Specify the table to which you want to replicate columns, and then click Next.
3. Select one or more columns, and then click Finish to replicate them to the selected table.
   Note: Replicas are, by default, read-only copies of objects. Any changes made to the original column are automatically propagated to the replica. This synchronization is controlled by a replication object for each replica, a list of which is available by selecting Model > Replications. To revert a column denormalization, simply delete the duplicated column from the target table property sheet. For detailed information about working with replicas and replications, see Core Features Guide > Linking and Synchronizing Models > Shortcuts and Replicas.

   In this example, to obtain the division name on the pay slip of each employee without requiring a link to the Division table, the DivisionName column is replicated to the PaySlip table:

   Before	After