SQL & PL/SQL

Hi All,

Can someone please tell me know how to reset pl/sql table to a NULL value or its equivalent before repopulating it.

   TYPE column_val_rec IS RECORD

   (column_name      VARCHAR2(30),

    column_type      VARCHAR2(30),

     char_value       VARCHAR2(2000),

    number_value     NUMBER,

    date_value       DATE,

     timestamp_value  TIMESTAMP

   );

  TYPE column_val_tbl IS TABLE OF column_val_rec INDEX BY BINARY_INTEGER;

In declaration it is

l_ClVars  column_val_tbl;

I want to reset l_ClVars  before populating it .If I just put  l_ClVars :=NULL; it gives

PLS-00382: expression is of wrong type

Can someone please let me know how can we reset this pl/sql table.

Thanks a lot.