Answer
IFS distinguishes three broad categories of database view. Base views are the default, unconditioned view fetching all columns directly from a table, typically sharing the table's own name minus its _TAB suffix, with no filtering conditions of its own. Report views are specifically built to back reports, generally named with a _REP suffix, built from a table or joined tables/views for that specific reporting purpose. Alternative views are any view built by adding extra columns, adding conditions, or joining multiple tables/views together for a specific purpose beyond the plain base view — this category includes custom-field views (_CFV) as well as other suffix patterns like _UIV, _PUB, _BI, _LOV, and _LIST, each created to serve some specific functional purpose beyond what the base view alone provides.