1

我有以下问题。在我的应用程序中，用户使用特殊系统（强度、感知等，值从 1 到 10）创建游戏角色。在保存或之后（通过调用过程），我需要根据特殊参数值计算字符统计信息。我怎样才能做到这一点 ？这是关系方案：

在此处输入图像描述

这是SQL代码：

create table Player (
  id_player numeric,
  player_name varchar2(50) not null,
  age decimal not null,
  strength decimal not null,
  perception decimal not null,
  endurance decimal not null,
  charisma decimal not null,
  inteligence decimal not null,
  agility decimal not null,
  luck decimal not null,
  caps decimal not null,
  statistics numeric,
  CONSTRAINT chk_s check (strength <= 10),
  CONSTRAINT chk_p check (perception <= 10),
  CONSTRAINT chk_e check (endurance <= 10),
  CONSTRAINT chk_c check (charisma <= 10),
  CONSTRAINT chk_i check (inteligence <= 10),
  CONSTRAINT chk_a check (agility <= 10),
  CONSTRAINT chk_l check (luck <= 10),
  CONSTRAINT unique_name UNIQUE (player_name),

  CONSTRAINT PLAYER_PK primary key (id_player)
);

create table Player_derived_statistics(
  id_statistics numeric,
  carry_weight decimal,
  hit_points decimal,
  radiation_resistance decimal,

  CONSTRAINT DERIVED_STATISTICS_PK primary key (id_statistics)
);

alter table Player add constraint PLAYER_DERIVED_STATISTICS_FK1 foreign key (statistics) references Player_derived_statistics (id_statistics);

并查询返回所有参数：

SELECT p.strength, p.perception, p.endurance, p.charisma, p.inteligence, p.agility, p.luck
from player p inner join player_derived_statistics s on s.id_statistics = p.statistics;

所以最后我希望能够计算每个玩家的carry_weight、hit_points 和radiation_resistance。假设所有公式都是(player_parameter * 10) + 150. 使用什么会更好：触发器或过程？

编辑

我正在尝试使用答案中的代码，但出现错误Encountered the symbol "INNER" when expecting one of the following: ( ...。

CREATE OR REPLACE PACKAGE pkg_player_stats AS
  FUNCTION get_derived_stats( p_id_player IN player.id_player%TYPE )
    RETURN derived_stats_rec
  IS
    l_stats_rec derived_stats_rec;
  BEGIN
    SELECT (p.strength*10)+150,
           (p.endurance*20)+150,
           ((p.endurance-1)*2)/100
      INTO l_stats_rec.carry_weight,
           l_stats_rec.hit_points,
           l_stats_rec.radiation_resistance
      FROM (
        SELECT p.strength,  
               p.endurance
          from player p inner join player_derived_statistics s on s.id_statistics = p.statistics);
    RETURN l_stats_rec;
  END get_derived_stats;
END;
4

2 回答 2

0

为什么需要两张桌子？我会去

  • 一个仅包含所有 SPECIAL 统计信息的表和一个计算派生统计信息的视图（在您的应用程序中，您将查询该视图）：

    CREATE VIEW player_v AS 
SELECT p.strength, ..., /* all attributes */
       p.strength * 10 + 150 as carry_weight,
       p.endurance * 20 + 150 as hit_points,
       (p.endurance - 1) * 2 / 100 as radiation_resistance
  FROM player p

  • 带有您使用触发器更新的派生列的单个表：

    CREATE OR REPLACE TRIGGER player_ins_up_trg 
   BEFORE UPDATE OR INSERT ON player
   FOR EACH ROW
BEGIN
   :new.carry_weight := :new.strength * 10 + 150;
   :new.hit_points := :new.endurance * 20 + 150;
   :new.radiation_resistance := (:new.endurance - 1) * 2 / 100;
END;

  • 如果您使用的是 Oracle 11，您还可以使用虚拟列：

    虚拟列不存储在磁盘上。相反，数据库通过计算一组表达式或函数来按需派生虚拟列中的值。

    例如：

    ALTER TABLE player ADD (carry_weight AS (strength * 10 + 150));
于 2011-01-28T08:47:03.237 回答
0

我绝对不会为这种事情使用触发器。听起来您需要一个接受 ID_PLAYER 参数并返回值或值记录的函数。像这样的东西（请注意，我不确定我是否理解您所描述的公式，所以我猜测了一下

CREATE OR REPLACE PACKAGE pkg_player_stats
AS
  TYPE derived_stats_rec IS RECORD (
    carry_weight NUMBER,
    hit_points   NUMBER,
    radiation_resistance NUMBER );

  FUNCTION get_derived_stats( p_id_player IN player.id_player%TYPE )
    RETURN derived_stats_rec;
END;

CREATE OR REPLACE PACKAGE pkg_player_stats
AS
  FUNCTION get_derived_stats( p_id_player IN player.id_player%TYPE )
    RETURN derived_stats_rec
  IS
    l_stats_rec derived_stats_rec;
  BEGIN
    SELECT carry_weight         * multiplier + 150,
           hit_points           * multiplier + 150,
           radiation_resistance * multiplier + 150
      INTO l_stats_rec.carry_weight,
           l_stats_rec.hit_points,
           l_stats_rec.radiation_resistance
      FROM (
        SELECT p.strength + 
               p.perception + 
               p.endurance +
               p.charisma + 
               p.inteligence +
               p.agility +
               p.luck multiplier,
               s.carry_weight,
               s.hit_points,
               s.radiation_resistance
          from player p 
               inner join player_derived_statistics s on s.id_statistics = p.statistics);
    RETURN l_stats_rec;
  END get_derived_stats;
END;
于 2011-01-28T05:06:04.370 回答