The VARRAY datatype is the most like a traditional array. Elements are of the same type and use a sequential numeric index. This means the index of VARRAY variables is densely populated. You opt to use a VARRAY when you know the number of items that will go in the collection before declaring the variable. Like arrays in other programming languages, the VARRAY cannot grow in size after it is declared. You should use a nested table or associative array when you aren’t sure whether you know the maximum number values in advance.