You can define collection types in a procedure, function, or package.
You can pass collection variables as parameters, to move data between client-side applications and stored subprograms.
It is a general concept that encompasses lists, arrays, and other familiar datatypes.
Each element has a unique subscript that determines its position in the collection.
Nested tables differ from arrays in two important ways: When you are writing original code or designing the business logic from the start, you should consider the strengths of each collection type to decide which is appropriate for each situation.