oracle ±Ê¼Ç VI Ö®Óαê (CURSOR)
Óαê(CURSOR),ºÜÖØÒª
Óαê:ÓÃÓÚ´¦Àí¶àÐмǼµÄÊÂÎñ
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1 ´¦ÀíÏÔʽÓαê
ÏÔʽÓα괦ÀíÐè 4¸ö PL/SQL ²½Öè,ÏÔʾÓαêÖ÷ÒªÓÃÓÚ´¦Àí²éѯÓï¾ä
(1) ¶¨ÒåÓαê
¸ñʽ: CURSOR cursor_name [(partment[,parameter]...)] IS select_statement;
¶¨ÒåµÄÓα겻ÄÜÓÐ INTO ×Ó¾ä
(2) ´ò¿ªÓαê
OPEN cursor_name[...];
PL/SQL ³ÌÐò²»ÄÜÓà OPEN Óï¾äÖØ¸´´ò¿ªÒ»¸öÓαê
(3)ÌáÈ¡ÓαêÊý¾Ý
FETCH cursor_name INTO {variable_list | record_variable};
(4) ¹Ø±ÕÓαê
CLOSE cursor_name;
Àý 1 ²éѯǰ 10 ÃûÔ±¹¤µÄÐÅÏ¢
declare
--¶¨ÒåÓαê
cursor c_cursor is select last_name,salary from employees where rownum < 11 order by salary;
v_name employees.last_name%type;
V_sal employees.salary%type;
begin
--´ò¿ªÓαê
open c_cursor;
-- ÌáÈ¡ÓαêÊý¾Ý
fetch c_cursor into v_name,v_sal;
while c_cursor %found loop
dbms_output.put_line(v_name || ':' || v_sal);
fetch c_cursor into v_name,v_sal;
end loop;
--¹Ø±ÕÓαê
close c_cursor;
end;
----------------------------------
Á·Ï°: ÊäÈ벿ÃźŠdep_id,²éѯ¸Ã²¿Ãŵį½¾ù¹¤×Ê : avg_sal,Ô±¹¤¹¤×ÊΪ salary
Èô salary < avg_sal - 500 ¹¤×ÊÕÇ 500
Èô avg_sal - 500 <= salary < avg_sal + 500 ¹¤×ÊÕÇ 300
Èô
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CRUD
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create,alter,drop,rename,truncate(Çå¿Õ)
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grant,revoke
TCL(Transaction Control): ÊÂÎñ¿ØÖÆÓïÑÔ,ÓëÊÂÎñÓйØ
commit,rollback,savepoint
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1.ASCII
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SQL> select ascii(’A’) A,ascii(’a’) a,ascii(’0’) zero,ascii(’ ’) space from dual;
A A ZERO SPACE
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65 97 48 32
2.CHR
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