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我正在使用 python 脚本为我观看的动漫节目创建和维护一个 sqlite 数据库，以帮助我更好地跟踪它们以及我拥有和需要获得的剧集。

我使用该脚本为每个系列创建一个表，例如 Bleach、Black Lagoon... 并且在每个表中都存储了以下信息：

系列表：

Season_Num         # Unique season number
I_Have_Season      # yes or no to say I have a directory for that season
Season_Episodes    # Amount of episodes according to the TVDB that are in that season
Episodes_I_Have    # The numer of episodes I have for that season

为我拥有的每个系列创建同一张表，并为该系列中的每个季节创建一行，似乎工作正常。

现在我要做的是创建一个汇总表，它从每个系列的表中获取信息，并只创建一个包含我需要的所有信息的表，它具有以下信息：

汇总表：

Series          # Unique Series name
Alt_Name        # Alternate name (The series name in english)
Special_Eps     # The amount of Special episodes (Season 0 in the series table)
Special_Eps_Me  # The number of Special Episodes I have
Tot_Ses         # The total count of the Seasons (excluding season 0)
Tot_Ses_Me      # The total count of Seasons that have yes in I_Have_Season column
Tot_Episodes    # Total Episodes excluding season 0 episodes
Tot_Eps_Me      # Total Episodes I have excluding season 0 episodes

我认为我想做的事情可以使用触发器来完成，但我不确定如何实现它们，以便汇总表将自动更新，例如，如果将新季节添加到系列表或系列表的值发生更改。

更新：

经过更多的思考和研究之后，Fabian 的视图而不是表格的想法听起来可能是我想要的，但如果可能的话，我想将每个系列单独保存在自己的表格中以进行更新，而不是每个系列只有一个表格每个季节都混在一起。

更新 2：

我已经继续并为 INSERT、UPDATE 和 DELETE 添加了触发器，我在脚本的初始创建循环中添加了它们，使用变量作为表名，汇总表似乎正在更新（在修复了一些值如何在是计算出来的）。我会进一步测试它，希望它会继续工作。现在我只需要让我的脚本为新系列和我删除的系列添加和删除表。

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1 回答 1

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这可以使用触发器来实现。但是这种事情通常最好以声明方式完成，使用视图：

例如，

create table series (
  series_name,
  alt_name,
  special_eps,
  special_eps_me,
  primary key(series_name)
);

create table seasons (
  series_name,
  season_num,         
  i_have_season, 
  episodes, 
  episodes_i_have,
  primary key (series_name,season_num),
  foreign key (series_name) references series (series_name),
  check (i_have_season in ('F','T'))
);

create view everything_with_counts as 
select series_name, 
       alt_name, 
       special_eps, 
       special_eps_me, 
       (select count(*) from seasons  where seasons.series_name = series.series_name) as tot_ses,
       (select count(*) from seasons  where seasons.series_name = series.series_name and i_have_season = 'T') as tot_ses_me,
       (select sum(episodes) from seasons where seasons.series_name = series.series_name) as tot_epsiodes,
       (select sum(episodes_i_have) from seasons where seasons.series_name = series.series_name and i_have_season = 'T') as tot_epsiodes_me
from series;

编辑

由于您想坚持触发器设计：假设您有这样的系列表：

create table series_a (
  season_num,         
  i_have_season, 
  episodes, 
  episodes_i_have
);

create table series_b (
  season_num,         
  i_have_season, 
  episodes, 
  episodes_i_have
);

依此类推，您的汇总表如下：

create table summary (
  series_name,
  alt_name,
  special_eps,
  special_eps_me,
  tot_ses,
  tot_ses_me,
  tot_episodes,
  tot_episodes_me,
  primary key(series_name));

您必须为每个系列表创建三个触发器（插入、更新、删除），例如：

  create trigger series_a_ins after insert on series_a 
  begin
    update summary set tot_ses = (select count(*) from series_a ),
                       tot_ses_me = (select count(*) from series_a  where  i_have_season = 'T'),
                       tot_episodes = (select sum(episodes) from series_a ),
                       tot_episodes_me = (select sum(episodes_i_have) from series_a where  i_have_season = 'T') 
    where series_name = 'a';
  end;

/* create trigger series_a_upd after update on series_a ... */
/* create trigger series_a_del after delete on series_a ... */

在此版本中，您必须在汇总表中手动添加汇总条目，然后当您修改 series_... 表时，计数器会自动更新。

您还可以使用 INSERT OR REPLACE（请参阅文档）按需创建摘要条目。

于 2013-10-27T13:55:53.770 回答