The ability to nest blocks in PL/SQL will allow you to better organize your programs. Blocks can be used to prevent variables from being accessed improperly and to allow exceptions to be handled effectively.
begin dbms_output.put_line('In the main block.'); begin dbms_output.put_line('In a nested block.'); end; end;
This is a simple example of how PL/SQL blocks can be nested inside of one another. When the example is run, the two lines of text are printed out in sequence. This shows that when a BEGIN keyword is encountered during normal execution (rather than in the context of a raised error) control will drop to the nested block.