Sql updating table variable
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 can be stored in a database column, but associative arrays cannot.
Nested tables are appropriate for important data relationships that must be stored persistently.
You must update or retrieve all elements of the varray at the same time, which is most appropriate when performing some operation on all the elements at once.
But you might find it impractical to store and retrieve large numbers of elements this way.
Nested tables and varrays can also be attributes of object types.
PL/SQL nested tables are like one-dimensional arrays.
You can model multi-dimensional arrays by creating nested tables whose elements are also nested tables.
Collections follow the same scoping and instantiation rules as other types and variables.
In a block or subprogram, collections are instantiated when you enter the block or subprogram and cease to exist when you exit.