Editing EPrints4 Core Roadmap (section)

==Data retrieval and searching==

I think there are two slightly different aspects of data retrieval:

* an internal mechanism for retrieving data straight from the database, for instance:
** all data objects belonging to a dataset
** all data objects owned by a user
** generally the retrieval of data objects based on an EXACT constraint or set of constraints.
** possibility to order the data objects by a given meta field (i.e. a DB column).
* a user search optimised for helping users to find content they're interested to. This will likely be done by Xapian. Because this concept can become difficult to implement, it is better to use a specialist tool such as Xapian to do it. Includes the following scenarios:
** retrieval of all data objects belonging to a dataset (via the Xapian indexes which may be out-of-date or incomplete since objects are indexed by the indexer in a asynchronous manner)
** parsing complex user queries using e.g. boolean operators

One question is how to label these two slightly different searching mechanism?

===Internal Data retrieval===

* Only supports EXACT matching or other SQL-derived tests and operators e.g. NOT NULL (aka is_set)
* Tightly linked to the concept of EPrints::List
* May be used on the UI to display lists of items owned by a user ETC but shouldn't be used in real user searches

===User Searches===

* Requires the creation and management of indexes (because it is the indexes which are searched)