PostgreSQL mengatur bidang objek JSON dalam array JSON

Ini dimungkinkan dengan membuat ulang larik json pada setiap pembaruan.

SQL untuk pembuatan tabel dan contoh penyisipan data:

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"}]');

Data yang dimasukkan:

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

Perbarui kueri:

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;

Hasil kueri:

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

Kueri bekerja dengan cara berikut:

1. Ubah array json menjadi baris json dan filter dengan game Properti. Ini dilakukan dengan membuat json_rows CTE.

2. Perbarui data json di baris json tempat pengguna "Joe" ditemukan.

3. Setelah Anda memiliki nilai json baru, lakukan pembaruan berdasarkan id.

Catatan: Seperti yang Anda lihat, dalam implementasi saat ini, array json dibuat ulang (hanya di baris yang perlu diperbarui). Ini dapat menyebabkan perubahan urutan elemen di dalam array.