更新 jsonb PostgreSQL 中数组的对象字段

Question

我在 PostgreSQL 中有以下 table：

CREATE TABLE resume (
  resume_id UUID PRIMARY KEY,
  data JSONB
);

在 table 里面，我有一列 data，它有 JSONB 数据类型，并且包含这样的值：

{"educations": [{"major": "MAJOR-1", "minor": "MINOR-1"}, {"major": "MAJOR-2", "minor": "MINOR-2"}]}

这里是测试数据：

INSERT INTO resume VALUES('7e29d793-a4ba-4bfb-a93a-c2d34b7a5c8a', '{"educations": [{"major": "MAJOR-1", "minor": "MINOR-1"}, {"major": "MAJOR-2", "minor": "MINOR-2"}]}');
INSERT INTO resume VALUES('7e29d793-a4ba-4bfb-a93a-c2d34b7a5c8b', '{"educations": [{"major": "ANOTHER-MAJOR-1", "minor": "ANOTHER-MINOR-1"}, {"major": "ANOTHER-MAJOR-2", "minor": "ANOTHER-MINOR-2"}]}');

但现在我需要将主要值和次要值转换为数组，因此，对于第一行，我希望收到以下结果：

{"educations": [{"major": ["MAJOR-1"], "minor": ["MINOR-1"]}, {"major": ["MAJOR-2"], "minor": ["MINOR-2"]}]}

对于第二行，我希望收到此结果：

 {"educations": [{"major": ["ANOTHER-MAJOR-1"], "minor": ["ANOTHER-MINOR-1"]}, {"major": ["ANOTHER-MAJOR-2"], "minor": ["ANOTHER-MINOR-2"]}]}

现在我创建了这个查询来更新 major:

with sub as (
    select pos - 1 as elem_index, elem, resume_id
    from resume, jsonb_array_elements(data -> 'educations') with ordinality arr(elem, pos)
)
update resume cv
set data = jsonb_set(data, array['educations', sub.elem_index::text, 'major'], ('[' || (sub.elem -> 'major')::text || ']')::jsonb, true)
from sub
where cv.resume_id = sub.resume_id

但是它只更新了所有行的数组的第一个元素，所以现在我收到这个结果：

{"educations": [{"major": ["MAJOR-1"], "minor": "MINOR-1"}, {"major": "MAJOR-2", "minor": "MINOR-2"}]}
{"educations": [{"major": ["ANOTHER-MAJOR-1"], "minor": "ANOTHER-MINOR-1"}, {"major": "ANOTHER-MAJOR-2", "minor": "ANOTHER-MINOR-2"}]}

所以我的问题是如何解决这个问题？请帮助我:)

Answer 1

方案一：jsonb更新基于jsonb_set

jsonb_set() 无法对相同的 jsonb 数据进行多次更新，因此您需要基于 jsonb_set() 创建一个 aggregate 函数，该函数将迭代一组行：

CREATE OR REPLACE FUNCTION jsonb_set(x jsonb, y jsonb, p text[], z jsonb, b boolean)
RETURNS jsonb LANGUAGE sql IMMUTABLE AS
$$ SELECT jsonb_set(COALESCE(x, y), p, z, b) ; $$ ;

CREATE OR REPLACE AGGREGATE jsonb_set_agg(x jsonb, p text[], z jsonb, b boolean)
( SFUNC = jsonb_set
, STYPE = jsonb
) ;

然后你可以在下面的查询中使用聚合函数jsonb_set_agg():

SELECT jsonb_set_agg(r.data, array['educations', (a.id - 1) :: text, b.key], to_jsonb(CASE WHEN b.value IS NULL THEN array[] :: text[] ELSE array[b.value] END), True)
  FROM resume AS r
 CROSS JOIN LATERAL jsonb_array_elements(r.data->'educations') WITH ORDINALITY AS a(data, id)
 CROSS JOIN LATERAL jsonb_each_text(a.data) AS b
 WHERE b.key = 'major' OR b.key = 'minor'
 GROUP BY resume_id

最后在更新语句中：

WITH sub AS (
SELECT jsonb_set_agg(r.data, array['educations', (a.id - 1) :: text, b.key], to_jsonb(CASE WHEN b.value IS NULL THEN array[] :: text[] ELSE array[b.value] END), True)
  FROM resume AS r
 CROSS JOIN LATERAL jsonb_array_elements(r.data->'educations') WITH ORDINALITY AS a(data, id)
 CROSS JOIN LATERAL jsonb_each_text(a.data) AS b
 WHERE b.key = 'major' OR b.key = 'minor'
 GROUP BY resume_id
)
UPDATE resume cv
   SET data = sub.data
  FROM sub
 WHERE cv.resume_id = sub.resume_id

解决方案 2：分解并重建 jsonb 数据

SELECT jsonb_agg(c.data ORDER BY c.id)
  FROM
     ( SELECT resume_id
            , a.id
            , jsonb_object_agg(b.key,to_jsonb(CASE WHEN b.value IS NULL THEN array[] :: text[] ELSE array[b.value] END)) AS data
         FROM resume AS r
        CROSS JOIN LATERAL jsonb_array_elements(r.data->'educations') WITH ORDINALITY AS a(data, id)
        CROSS JOIN LATERAL jsonb_each_text(a.data) AS b
        GROUP BY resume_id, a.id
     ) AS c
 GROUP BY c.resume_id

查看dbfiddle中的测试结果。

更新 jsonb PostgreSQL 中数组的对象字段

Update object field of array in jsonb PostgreSQL

sql

postgresql

sql-update

postgresql-json

jsonb