what is bulk collect?

BULK COLLECT

Bulk binds can improve the performance when loading collections from a queries. The BULK COLLECT INTO construct binds the output of the query to the collection.

It can be used with all three types of collections: associative arrays, nested tables, and VARRAYs.

You can fetch into individual collections (one for each expression in the SELECT list) or a single collection of records.

The collection is always populated densely, starting from index value 1.

If no rows are fetched, then the collection is emptied of all elements.