Chapter 7 Denormalizing a PDM

Vertical partitioning

Vertical partitioning consists in segmenting a table into multiple tables each containing a subset of columns and the same number of rows as the partitioned table. The partition tables share the same primary key.

Example

The table Customer contains the following columns:

This table can be divided in two tables corresponding to different aspects of the table. You can use the Vertical Partitioning Wizard to split the table as follows:

Pros and cons

Vertical partitioning allows queries to scan less data thus improves the query response time. It also allows you to split data requiring different levels of protection, you can store confidential information in a special partition.

However, vertical partitioning also implies to:

Create joins and unions to retrieve related data from multiple tables
Create more intelligent queries to determine which table contains the requested data
Additional metadata to describe the partitioned table