A data storage and retrieval system with parameterized category
definitions and dynamically generated search indices. A parameterized
category definition for a family of categories is obtained consisting of
a parameterized predicate, such that parameter values can be provided
with a search query to identify information items that match a category
within the family of categories. The parameterized category definition is
divided into a parameterized part and a static part. The static part is
used to create associations between information items and the family of
categories. The disclosed system processes the parameterized part of the
category family definition to dynamically generate one or more search
indices. The disclosed system determines whether any existing indices
match the parameters of the parameterized part, and can accordingly be
re-used. In the case where one or more indices are missing that are
needed to support the parameterized part of the category family
definition, the disclosed system operates to create them based on
information items associated with the family of categories based on the
static part of the parameterized category definition. Queries supplying
values for the parameters of the parameterized category definition for
the family of categories are subsequently processed to identify
information items belonging to specific, dynamically defined categories
within the family of categories.