我怀疑你正在寻找COUNT
方法,即
DECLARE
l_local_collection dbfowner.rpt_wire_import_tabletype;
BEGIN
SELECT sysdate + level
BULK COLLECT INTO l_local_collection
FROM dual
CONNECT BY level <= 10;
dbms_output.put_line( 'l_local_collection contains ' ||
l_local_collection.count ||
' elements.' );
END;
像任何局部变量一样,l_local_collection
将具有声明它的块的范围。数据存储在会话的 PGA 中。集合中的数据不是永久的。
您可以从本地集合中选择
SQL> create type some_object as object (
2 rec_value_date date
3 );
4 /
Type created.
SQL> create type some_coll
2 as table of some_object;
3 /
Type created.
SQL> ed
Wrote file afiedt.buf
1 declare
2 l_local_collection some_coll;
3 begin
4 select some_object( sysdate + numtodsinterval( level, 'day' ) )
5 bulk collect into l_local_collection
6 from dual
7 connect by level <= 10;
8 for x in (select * from table( l_local_collection ))
9 loop
10 dbms_output.put_line( x.rec_value_date );
11 end loop;
12* end;
SQL> /
20-AUG-12
21-AUG-12
22-AUG-12
23-AUG-12
24-AUG-12
25-AUG-12
26-AUG-12
27-AUG-12
28-AUG-12
29-AUG-12
PL/SQL procedure successfully completed.
但是一般来说,将所有数据从 SQL VM 拉到 PL/SQL VM 中,然后将所有数据传回 SQL VM 以发出SELECT
语句,通常是没有意义的。将数据保存在 SQL 中或定义流水线表函数以返回数据通常更有意义。
如果您只想遍历集合中的元素
SQL> ed
Wrote file afiedt.buf
1 declare
2 l_local_collection some_coll;
3 begin
4 select some_object( sysdate + numtodsinterval( level, 'day' ) )
5 bulk collect into l_local_collection
6 from dual
7 connect by level <= 10;
8 for i in 1 .. l_local_collection.count
9 loop
10 dbms_output.put_line( l_local_collection(i).rec_value_date );
11 end loop;
12* end;
SQL> /
20-AUG-12
21-AUG-12
22-AUG-12
23-AUG-12
24-AUG-12
25-AUG-12
26-AUG-12
27-AUG-12
28-AUG-12
29-AUG-12
PL/SQL procedure successfully completed.
迭代集合中的元素会更有意义,它将所有内容保存在 PL/SQL 中,而不是SELECT
从集合中迭代,后者将所有数据强制返回 SQL VM。