oracle开发学习篇之集合函数

集合函数;

declare 

        type list_nested is table of varchar2(100) not null;

        v_all list_nested := list_nested('changan','hubei','shanghai','beijing','Android','Java-Android');

BEGIN

        v_all.delete(1);

        for x in v_all.first .. v_all.last loop

            dbms_output.put_line(v_all(x));

        end loop;

        --dbms_output.put_line('list leng:' || v_all.count );

end;

/





declare 

        type list_nested is table of varchar2(100) not null;

        v_all list_nested := list_nested('changan','hubei','shanghai','beijing','Android','Java-Android');

BEGIN

        v_all.delete(1,3); --指定删除索引范围的数据;

        for x in v_all.first .. v_all.last loop

            dbms_output.put_line(v_all(x));

        end loop;

        dbms_output.put_line('list leng:' || v_all.count );

end;

/







declare 

        type list_nested is table of varchar2(100) not null;

        v_all list_nested := list_nested('changan','hubei','shanghai','beijing','Android','Java-Android');

BEGIN

        if v_all.EXISTS(1) then

            dbms_output.put_line('索引为1的数据存在');

        end if;

        if not v_all.EXISTS(10) then

            dbms_output.put_line('索引为10的数据不存在');

        end if;

    end;

/







declare

        type list_nested is table of varchar2(100) not null;

        v_all list_nested := list_nested('FireFox','firefox.com','www.firefox.com');

begin

        dbms_output.put_line('原始长度' || v_all.count);

        v_all.extend(2);

        dbms_output.put_line('扩充之后长度' || v_all.count);

        v_all(4) := 'www.google.com';

        v_all(5) := 'Google.com';

        for x in v_all.first  .. v_all.last loop

            dbms_output.put_line(v_all(x));

        end loop;

    end;

/



范例

    扩充集合长度，并使用已有内容填充

declare

        type list_nested is table of varchar2(100) not null;

        v_all list_nested := list_nested('FireFox','firefox.com','www.firefox.com');

begin

        dbms_output.put_line('原始长度' || v_all.count);

        v_all.extend(2 , 3);

        dbms_output.put_line('扩充之后长度' || v_all.count);

        for x in v_all.first  .. v_all.last loop

            dbms_output.put_line(v_all(x));

        end loop;

    end;

/





范例

    集合函数count limit

declare

    type list_varray is  varray(20) of varchar2(100);

    v_info list_varray := list_varray('firefox.com','www.firefox.com','www.oracle.com');

begin

    dbms_output.put_line('数组集合的最大长度' || v_info.limit);

    dbms_output.put_line('数组集合的数据量' || v_info.count);

end;

/





declare

        type info_index is table of varchar2(20) index by PLS_INTEGER;

        v_info info_index;

        v_foot number;

begin

        v_info(1) := 'FireFox';

        v_info(10) := 'Java';

        v_info(-10) := 'oracle';

        v_info(-20) := 'EJB';

        v_info(30) := 'Android';

        v_foot := v_info.first;

        while (v_info.exists(v_foot)) loop

            dbms_output.put_line('v_info (' || v_foot ||') = ' || v_info(v_foot);

            v_foot := v_info.next(v_foot) ;

        end loop;

    end;

/ 





declare

        type info_index is table of varchar2(20) index by PLS_INTEGER;

        v_info info_index;

        v_foot number;

begin

        v_info(1) := 'FireFox';

        v_info(10) := 'Java';

        v_info(-10) := 'oracle';

        v_info(-20) := 'EJB';

        v_info(30) := 'Android';

        DBMS_OUTPUT.put_line('索引为10的下一个索引是:' || v_info.next(10));

        dbms_output.put_line('索引为-10的上一个索引是:' || v_info.prior(-10));

    end;

/ 





declare 

        type list_varray is varray(8) of varchar2(50);

        v_info list_varray :=  list_varray('FireFox','www.FireFox','www.Google.com','EJB');

begin

        dbms_output.put_line();

        for x in v_info.first .. v_info.last loop

                dbms_output.put_line(v_info(x));

        end loop;

    end;

/

declare 

        type list_varray is varray(8) of varchar2(100);

        v_info list_varray := list_varray('FireFox','www.firefox.com','oracle','oracle_username');

begin

        dbms_output.put_line('删除集合之前的数量:' || v_info.count);

        v_info.trim; -- 删除一个数据;

        dbms_output.put_line('v_info.trim 删除集合之后的数据量 :' || v_info.count);

        v_info.trim(2); -- 删除2个数据;

        dbms_output.put_line('v_info.trim(2) 删除集合之后的数据量 :' || v_info.count);

        for x in v_info.first .. v_info.last loop

            dbms_output.put_line(v_info(x));

        end loop;

    end;

/