oracle开发学习篇之集合运算符以及集合异常捕获

--取出集合;长度

declare

        type list_nested is table of varchar2(50) not null;

        v_all list_nested := list_nested('a','b','c','d','c','d');

begin

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

end;

/



--从集合中取出取消重复的元素

declare

        type list_nested is table of varchar2(50) not null;

        v_all list_nested := list_nested('a','b','c','d','c','d');

begin

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

end;

/



--判断集合是否为空

declare 

    type list_nested is table of varchar2(50) not null;

    v_allA list_nested := list_nested('shanghai','beijing','changan');

    v_allB list_nested := list_nested('shanghai');

begin

    if v_allA is not empty then

        dbms_output.put_line('v_allA not null!');

    end if;

    if v_allB is empty then

        dbms_output.put_line('v_allB is null!');

    else

        dbms_output.put_line('v_allB not null!!');

    end if;

end;

/





--判断字符是否存在

declare 

    type list_nested is table of varchar2(50) not null;

    v_allA list_nested := list_nested('shanghai','beijing','changan');

    v_allB list_nested := list_nested('shanghai');

    v_str  varchar2(20) := 'shanghai';

begin

    if v_str member of v_allA  then

        dbms_output.put_line('shanghai value is exists');

        end if;

end;

/(





--使用for循环遍历集合的每一个元素; 取出list中交集

declare

    type list_nested is table of varchar2(50) not null;

    v_allA list_nested := list_nested('shanghai','beijing','hunan');

    v_allB list_nested := list_nested('Java','beijing','tianjing');

    v_newlist         list_nested ;

BEGIN

    v_newlist := v_allA multiset except v_allB;

    for x in 1 .. v_newlist.count loop

        dbms_output.put_line(v_newlist(x));

    end loop;

end;

/



--使用for循环遍历集合的每一个元素; 取出集合中所有的元素

declare

    type list_nested is table of varchar2(50) not null;

    v_allA list_nested := list_nested('shanghai','beijing','hunan');

    v_allB list_nested := list_nested('Java','beijing','tianjing');

    v_newlist         list_nested ;

BEGIN

    v_newlist := v_allA multiset union v_allB;

    for x in 1 .. v_newlist.count loop

        dbms_output.put_line(v_newlist(x));

    end loop;

end;

/



判断集合是否为集合

declare

    type list_nested is table of varchar2(50) not null;

    v_allA list_nested := list_nested('shanghai','beijing','Java');

begin

    if v_allA is  A set then

        dbms_output.put_line('v_allA is list');

        end if;

end;

/



declare

    type list_nested is table of varchar2(50) not null;

    v_allA  varchar2(20) :=  'a';

begin

    if v_allA is  A set then

        dbms_output.put_line('v_allA is list');

        end if;

end;

/







--判断B是否为A的子集合

declare

    type list_nested is table of varchar2(50) not null;

    v_allA list_nested := list_nested('shanghai','beijing','hunan','Java');

    v_allB list_nested := list_nested('Java','beijing');

BEGIN

    if v_allB  submultiset v_allA then

        dbms_output.put_line('v_allB is v_allA submultiset');

    end if;

end;

/

--集合的异常处理;

--理解集合异常的缠身及处理操作; 所有异常捕获都能够使用others进行捕获;



DECLARE

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

        v_info list_varray; --此时的集合变量没有初始化

BEGIN

        v_info(0) := 10;  --此集合未初始化，所以会存在错误，

exception

        when collection_is_null then

        dbms_output.put_line('The error collection is not initialized');

END;

/









DECLARE

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

        v_info list_varray := list_varray('shanghai','changan','facebook');    

BEGIN

        dbms_output.put_line(v_info(5));

exception

    when subscript_beyond_count then

        dbms_output.put_line('索引值超过定义的元素个数!!');

    end;

/







DECLARE

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

        v_info list_varray := list_varray('shanghai','changan','facebook');    

BEGIN

        dbms_output.put_line(v_info('1'));

        dbms_output.put_line(v_info('a'));    

exception

    when value_error then

        dbms_output.put_line('索引值类型错误');

    end;

/







declare

        type info_index is table of varchar2(100) index by PLS_INTEGER;

        v_info info_index;

begin

        v_info(1) := 'fireof';

        v_info(2) := 'firefox.com';

        v_info(3) := 'www.firefox.com';

        v_info.delete(1);

        dbms_output.put_line(v_info(1));

        dbms_output.put_line(v_info(2));

        dbms_output.put_line(v_info(3));

exception

    when no_data_found then

        dbms_output.put_line('data not found !!!');

end;

/