Using the Collection Methods

The collection methods below help to generalize the code and make collections easier to use and also make your applications easier to maintain:

EXISTS

COUNT

LIMIT

FIRST and LAST

PRIOR and NEXT

EXTEND

TRIM

DELETE

A collection method is a built-in function or the process that operates on collections and is called using the dot notation. The syntax is as shown below:

collection_name.method_name[(parameters)]

The Collection methods can be called from the procedural statements but not from the SQL statements. The COUNT, EXISTS, LIMIT, FIRST, PRIOR, LAST, & NEXT are the functions, that appear as a part of an expression. And EXTEND, DELETE, and TRIM are the procedures that appear as a statement. Also, the EXISTS, TRIM, PRIOR, NEXT, EXTEND, and DELETE take parameters. Each parameter should be an integer expression. Only the EXISTS can be applied to automatically null collections. Whenever you apply another method to such type of collections, then the PL/SQL raises COLLECTION_IS_NULL.