Collections—an overview
A collection is a homogeneous single dimensional structure, which constitutes an ordered set of elements of a similar type. Being a homogeneous structure, all elements are of the same data type. The structure of the element contains cells with a subscript. The elements reside in these cells to make the index as their location information. The subscript or cell index becomes identification of an element and is used for its access.
Structure of a collection type, SPORT, is shown in the following diagram. Note the subscript and elements into it. A new element, GOLF, enters at the last empty location and is represented as SPORT [6]:
A collection element can be of any valid SQL data type or a user-defined type. An element of the SQL primitive data type is a scalar value while an element of the user-defined type is an object type instance. A collection can be used within a PL/SQL program by declaring a PL/SQL variable of collection type. The local PL/SQL variable can hold...
