Question

我有一张名为stats的表

player_id team_id match_date  goal assist`  
        1       8  2010-01-01    1      1
        1       8  2010-01-01    2      0
        1       9  2010-01-01    0      5
  ...

我想知道一名球员何时达到里程碑（例如100个进球，100个助攻，500个进球......）当团队达到里程碑时，我也想知道我想知道哪个球员或球队首先达到100球，第二，第三......

我想用表格的触发器累计总数表player_accumulator（和team_accumulator）表将是


player_id total_goals total_assists
        1           3             6


team_id   total_goals total_assists
      8             3             1
      9             0             5

每次在stats表中插入一行时，触发器将插入/更新player_accumulator和team_accumulator表。
此触发器还可以验证玩家或团队是否已达到包含数字的里程碑表中的里程碑

milestone
      100
      500
     1000
      ...

表player_milestone将包含玩家达到的里程碑：

player_id  stat    milestone          date
        1  goal          100    2013-04-02
        1  assist        100    2012-11-19

<小时/> 有一种更好的方法来实现“里程碑”吗？没有触发器有一种最简单的方法吗？

我正在使用PostgreSQL

Answer 1

我只计算得分和球队得分的球员的所有进球和助攻。

在客户端（伪代码）中这样：

function insert_stat(player_id, team_id, match_date, goals, assists)
{
  if (goals>0) {
    player_goals_before = query('select count(goal) from stats where player_id=?',player_id);
    team_goals_before = query('select count(goal) from stats where team_id=?',team_id);
  }
  if (assists>0) {
    player_assists_before = query('select count(assist) from stats where player_id=?',player_id);
    team_assists_before = query('select count(assist) from stats where team_id=?',team_id);
  }
  query("insert into stats (player_id, team_id, match_date, goal, assist)\n"
    +"values (?, ?, ?, ?, ?)", player_id, team_id, match_date, goal, assist);

  if (goals>0) {
    if ( has_milestone(player_goals_before+goals) and !has_milestone(player_goals_before) ) {
      alert("player " + player_id + " reached milestone!")
    }
    if ( has_milestone(team_goals_before+goals) and !has_milestone(team_goals_before) ) {
      alert("team " + team_id + " reached milestone!")
    }
  }
  // etc
}

不要维护里程碑表，因为这会使数据库非规范化。我认为这是一个不成熟的优化。只有当上述内容真的不够快时（例如，当每个player_id或team_id有统计数据的行数超过几千行时），您才可以考虑维护里程碑表。

如何实施系统以确定是否已达到里程碑

1 个答案: