使用 postgres 9.4 将 JSON 元素附加到数组

Question

我正在尝试将 JSON 元素附加到我的数据库中已经存在的数组中。我知道 jsonb_set 但是我无法升级到 Postgres 9.4，因为这是一个 groovy 项目，Maven 上的最新 postgresql 版本是 9.4。

我目前有一个这样的json结构：

"playersContainer": {
        "players": [
            {
                "id": "1",
                "name": "Nick Pocock",
                "teamName": "Shire Soldiers",
                "bio" : "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nulla imperdiet lorem tellus, in bibendum sem dignissim sed. Etiam eu elit sit amet lacus accumsan blandit sed ut dolor. Mauris vel dui non nisi vestibulum commodo vel id magna. Donec egestas magna in tincidunt mollis. Fusce mauris arcu, rhoncus ut lacus sed, fermentum ultrices elit. In sollicitudin at ex dapibus vestibulum. Pellentesque congue, est id lobortis viverra, mauris lectus pharetra orci, ut suscipit nisl purus vehicula est. Aliquam suscipit non velit vel feugiat. Quisque nec dictum augue.",
                "ratings": [
                    1,
                    5,
                    6,
                    9
                ],
                "assists": 17,
                "manOfTheMatches": 20,
                "cleanSheets": 1,
                "data": [
                    3,
                    2,
                    3,
                    5,
                    6
                ],
                "totalGoals": 19

            }
}

我想将新玩家添加到玩家数组并更新我的数据库，我尝试进行更新，但它擦除了其余数据。有没有办法定位玩家数组并将新的 json 对象附加到它？

Answer 1

很遗憾 9.4 没有 json_set 功能。你可以使用这样的东西：

WITH old_players AS (
       SELECT $1 AS j
  ), new_player AS (
       SELECT $2 AS j
  ), all_players AS (
       SELECT json_array_elements(j->'playersContainer'->'players') AS p
         FROM old_players
        UNION ALL
       SELECT *
         FROM new_player
  )      SELECT ('{"playersContainer": {"players": ' || json_agg(p) || '}}')::json
    FROM all_players
;

您可以将其用作函数：

CREATE OR REPLACE FUNCTION add_player(old_player json, new_player json) RETURNS json AS $$
WITH all_players AS (
       SELECT json_array_elements(($1)->'playersContainer'->'players') AS p
        UNION ALL
       SELECT $2
  ) 
  SELECT ('{"playersContainer": {"players": ' || json_agg(p) || '}}')::json
    FROM all_players
$$ LANGUAGE sql IMMUTABLE;

然后你就可以调用它了：

UPDATE site_content SET content = add_player(content, '{"id": "2",  "name": "Someone Else"}') where id = :id;