> -----Original Message-----
> From: Jonathan Lewis [mailto:[EMAIL PROTECTED]]
>
> If you declare a variable to be of
> table_name.column_name%type
> there are implicit constraints on the
> variable and any pl/sql assignments
> (in particular arithmetic operations)
> have to check that the result matches
> those constraints. At one time I believe
> this meant using a temporary variable
> to hold a result, then copying the result
> if the constraint was matched.
Could anyone explain this statement more fully? Why would there be "implicit constraints" when using table_name.column_name%rowtype vs. datatype? A simple test below showed no time difference.
SQL> create table t (d date not null primary key, n number) ;
Table created.
SQL> set timing on
SQL> -- using "datatype" declaration
SQL> declare
2 i pls_integer ;
3 dd date ;
4 begin
5 for i in 1..100000
6 loop
7 dd := sysdate ;
8 end loop ;
9 end ;
10 /
PL/SQL procedure successfully completed.
Elapsed: 00:00:09.54
SQL> -- using "table.column%type" declaration
SQL> declare
2 i pls_integer ;
3 dd t.d%type ;
4 begin
5 for i in 1..100000
6 loop
7 dd := sysdate ;
8 end loop ;
9 end ;
10 /
PL/SQL procedure successfully completed.
Elapsed: 00:00:09.34
