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Ò»¡¢dbms_random.normal
Õâ¸öº¯Êý²»´ø²ÎÊý£¬»á»Øµ½normal distributionµÄÒ»¸önumberÃÅÀ֮࣬ËùÒÔ´óµÖËæ»úÊý»áÔÚ-Ò»µ½Ò»Æä¼ä¡£
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SQL> declare
¶þ i number:=Áã;
Èý j number:=Áã;
ËÄ begin
Îå for k in Ò» .. 100000 loop
Áù i:= dbms_random.normal;
Æß if i > j
°Ë then j:=i;
¾Å end if;
Ê® end loop;
11 dbms_output.put_line(j);
12 end;
13 /
5.15325081797418404136433867107468983182
PL/SQL procedure successfully completed
¶þ¡¢dbms_random.random
Õâ¸öҲûÓвÎÊý£¬»ØÀ´Ò»¸ö´Ó-power(¶þ,31)µ½power(¶þ,31)µÄÕûÊýÖµ
Èý¡¢dbms_random.value
Õâ¸öº¯Êý·Ö³ÉÁ½ÖÖ£¬Ò»ÖÖÊÇû²ÎÊý£¬ÔòÖ±½Ó»ØÀ´Áã-Ò»Æä¼äµÄ38λСÊý
SQL > column value format 9.99999999999999999999999999999999999999
SQL > select dbms_random.value from dual;
VALUE
-----------------------------------------
.58983014999643548701631750396301271752
µÚ¶þÖÖÊǼÓÉÏÁ½¸ö²ÎÊýa¡¢b£¬Ôò»ØÀ´ÖµÔÚa¡¢bÆä¼äµÄ38λСÊý
SQL > column value format 999.999999999999999999999999999999999999
SQL > select dbms_random.value(100,500) value from dual;
VALUE
-----------------------------------------
412.150194612502916808701157054098274240
×¢Ò⣺ÎÞÂÛÊÇǰ·½¼¸Î»£¬Ð¡ÊýµãÒÔºó¶¼ÊÇ38λ
ËÄ¡¢dbms_random.string
Õâ¸öº¯ÊýÎñÐ뺬ÓÐÁ½¸ö²ÎÊý£¬Ç°·½µÄ×Ö·ûÖ¸¶¨ÃÅÀ࣬ºóÍ·µÄÊýÖµÖ¸¶¨Î»Êý(×î´ó60)
²¿Àà˵Ã÷£º
'u','U' : upper case alpha characters only
'l','L' : lower case alpha characters only
'a','A' : alpha characters only (mixed case)
'x','X' : any alpha-numeric characters (upper)
'p','P' : any printable characters
SQL > column value format a30
SQL > select dbms_random.string('u',30) value from dual;
VALUE
VTQNLGISELPXEDBXKUZLXKBAJMUTIA
SQL > select dbms_random.string('l',30) value from dual;
VALUE
------------------------------
uqygsbquingfqdytpgjvdoblxeglgu
SQL > select dbms_random.string('a',30) value from dual;
 
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begin
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