JSON数组中JSON对象的PostgreSQL集合字段

我有一张这样的桌子：

| id (SERIAL) | game (TEXT) | players (JSONB) |
+-------------+-------------+-----------------+
|      1      | chess       | [{name: Joe, role: admin}, {name: Mike, role: user}] |
|      2      | football    | [{name: Foo, role: user}, {name: Bar, role: user}] |
+-------------+-------------+-----------------+

| id (SERIAL) | game (TEXT) | players (JSONB) |
+-------------+-------------+-----------------+
|      1      | chess       | [{name: Joe, role: user}, {name: Mike, role: user}] |
|      2      | football    | [{name: Foo, role: user}, {name: Bar, role: user}] |
+-------------+-------------+-----------------+

我想将玩家（Joe）的角色设置为特定游戏（国际象棋）中的特定值（用户），因此结果如下所示：

| id (SERIAL) | game (TEXT) | players (JSONB) |
+-------------+-------------+-----------------+
|      1      | chess       | [{name: Joe, role: admin}, {name: Mike, role: user}] |
|      2      | football    | [{name: Foo, role: user}, {name: Bar, role: user}] |
+-------------+-------------+-----------------+

| id (SERIAL) | game (TEXT) | players (JSONB) |
+-------------+-------------+-----------------+
|      1      | chess       | [{name: Joe, role: user}, {name: Mike, role: user}] |
|      2      | football    | [{name: Foo, role: user}, {name: Bar, role: user}] |
+-------------+-------------+-----------------+

---

是否可以通过一个查询来实现这一点？

这可以通过在每次更新时重新创建json数组来实现

用于表创建和示例数据插入的SQL：

CREATE TABLE test_table(
  id BIGSERIAL PRIMARY KEY ,
  game TEXT,
  players JSONB
);

INSERT INTO test_table(game, players)
    VALUES
      ('chess', '[{"name": "Joe", "role": "admin"}, {"name": "Mike", "role": "user"}]'),
      ('football', '[{"name": "Foo", "role": "user"}, {"name": "Bar", "role": "user"}]');

插入的数据：

+----+----------+----------------------------------------------------------------------+
| id |   game   |                               players                                |
+----+----------+----------------------------------------------------------------------+
|  1 | chess    | [{"name": "Joe", "role": "admin"}, {"name": "Mike", "role": "user"}] |
|  2 | football | [{"name": "Foo", "role": "user"}, {"name": "Bar", "role": "user"}]   |
+----+----------+----------------------------------------------------------------------+

更新查询：

WITH json_rows AS
(SELECT id, jsonb_array_elements(players) as json_data FROM test_table
WHERE game = 'chess'),
 updated_rows AS (
    SELECT
      id,
      array_to_json(array_agg(
      CASE WHEN json_data -> 'name' = '"Joe"'
        THEN jsonb_set(json_data, '{role}', '"user"')
      ELSE json_data END)) as updated_json
    FROM json_rows
    GROUP BY id
)
UPDATE test_table SET players = u.updated_json
FROM updated_rows u
WHERE test_table.id = u.id;

查询结果：

+----+----------+---------------------------------------------------------------------+
| id |   game   |                               players                               |
+----+----------+---------------------------------------------------------------------+
|  2 | football | [{"name": "Foo", "role": "user"}, {"name": "Bar", "role": "user"}]  |
|  1 | chess    | [{"name": "Joe", "role": "user"}, {"name": "Mike", "role": "user"}] |
+----+----------+---------------------------------------------------------------------+

查询的工作方式如下：

将json数组转换为json行，并通过

game

属性对其进行过滤。这是通过创建

json_行

CTE来完成的

更新找到用户“Joe”的json行中的json数据

获得新的json值后，只需根据id进行更新

---

注意：如您所见，在当前的实现中，json数组被重新创建（仅在需要更新的行中）。这可能会导致数组中元素的顺序发生变化

我知道这会发生的。。。谢谢，但我知道你应该避免在关系数据库中使用JSON。我的用例非常特殊，需要JSON，否则我不会使用它。