Nested Block

AKA: Enclosed Blocks, Child Blocks or Sub-blocks. The higher level is called the Parent Block or the Enclosing Block.

Blocks have a scope. When a variable is in scope, it is visible, otherwise, it needs to be prefixed to be reference. Variables from the parent block are also visible. To reference variables from a package, prefix the item with the package name (pkg.var1)

These are particularly helpful for handling exceptions as control returns to the enclosing block, hence if it occurs in the outside block, the program will just stop.

Procedure/Function/Declare [Is/ Return]
 variables 
Begin
         Declare
         Begin
         Exception
         End;
Exception
End;