US Patent 10572450 Reducing database fragmentation

Techniques to reduce database fragmentation are disclosed. In various embodiments, an indication is received to store an attribute value for an entity that has a row or other entry in a first database table, wherein the first database table does not have a column for the attribute. It is determined that the value corresponds to a mapped value that is associated with not having an entry in a separate, second database table configured to store the attribute. Entries are made in the second database table only for values of the attribute other than the mapped value. Application level software code is configured to associate absence of a row in the second database table with the mapped value for the attribute.