Minimize database row sizes

Some databases have a maximum byte limit for the row length. Because each property that you create becomes a table column, you can exceed the row size limitation and receive an error when adding more property definitions to a class.

For row size limits for supported database engines, see Database Engine Differences.

For databases that have a maximum row size limit, users and application designers must take care to limit the number and size of the properties that are assigned to a class. The following suggestions can help you to avoid exceeding the row size limit.

• Allocate as little space as possible for the initial size of a string property. The size can be increased later. For production object stores, contact your IBM® support representative for information about reducing string column sizes.
• Consider the data type used for a string property because it can affect the row size. A string property with a large allocation size takes far less space in the row if it is created as a long string data type; however, long strings have functional limitations. Using an integer for representing values takes less space compared to a string. For more information about the differences between short and long string data types, see Short or long custom string properties in Selected property descriptions.
• Reduce the number of custom properties to a minimum number. Assigning properties to a class increases the row size.
• Eliminate unnecessary add-on features. Add-on features contain properties that increase the row size.

To calculate row size for existing DB2® tables, see Determine database row size.