Enterprise users rarely act on a single item. Bulk actions are a necessity.
The Selection State
When items are selected, the UI must shift modes. A persistent action bar should appear (often overriding the standard header or floating at the bottom of the viewport) indicating the number of selected items and available actions.
Cross-Page Selection
If your data spans multiple pages, the system must clearly state whether selection applies to the current page only or all records matching the current filter. This is a common source of catastrophic user error.
See also: Data Grid, Error Handling.