您的位置：首页 > 数据库

postgresql删除属性

2016-06-02 21:57 961 查看

PostgreSQL update and delete property from JSONB column

up vote 2 down vote favorite

From this article, I tried to update or delete property of a

JSONB

column:

CREATE TABLE xxx (id BIGSERIAL, data JSONB);
INSERT INTO xxx(data) VALUES( '{"a":1,"b":2}' );
SELECT * FROM data;
id |       data
----+------------------
1 | {"a": 1, "b": 2}

create the update function:

CREATE FUNCTION jsonb_merge(JSONB, JSONB)
RETURNS JSONB AS $$
WITH json_union AS (
SELECT * FROM JSONB_EACH($1)
UNION ALL
SELECT * FROM JSONB_EACH($2)
) SELECT JSON_OBJECT_AGG(key, value)::JSONB FROM json_union;
$$ LANGUAGE SQL;

testing:

-- replace
UPDATE xxx SET data = jsonb_merge(data,'{"b":3}') WHERE id = 1;
SELECT * FROM xxx;
id |       data
----+------------------
1 | {"a": 1, "b": 3}

-- append
UPDATE xxx SET data = jsonb_merge(data,'{"c":4}') WHERE id = 1;
SELECT * FROM xxx;
id |           data
----+-------------------------
1 | {"a": 1, "b": 3, "c": 4}

The question is:

is there any drawback of using

JSONB_EACH

(jsonb_merge) instead of

JSONB_EACH_TEXT

(from the article) in this case?

how to modify the

jsonb_merge

so if the second parameter property value is

null

(something like

{"b":null}

) the value would be erased?

.

-- remove
UPDATE xxx SET data = jsonb_merge(data,'{"b":null}') WHERE id = 1;
SELECT * FROM xxx;
id |       data
----+-----------------
1 | {"a": 1, "c": 4}

postgresql postgresql-9.4

share|improve this question

edited Mar 20 '15 at 10:23

asked Mar 20 '15 at 6:06

Kokizzu
273312

add a comment |

1 Answer 1

active oldest votes

up vote 3 down vote accepted

Question 1
There should be no signicant drawbacks. As the

value

is converted back to

jsonb

anyhow I would guess it would be more efficient to keep it that way the whole time.

Question 2
Just replace your function with the following (only the part

WHERE key NOT IN ...

added):

CREATE FUNCTION jsonb_merge(JSONB, JSONB)
RETURNS JSONB AS $$
WITH json_union AS (
SELECT * FROM JSONB_EACH($1)
UNION ALL
SELECT * FROM JSONB_EACH($2)
) SELECT JSON_OBJECT_AGG(key, value)::JSONB
FROM json_union
WHERE key NOT IN (SELECT key FROM json_union WHERE value ='null');
$$ LANGUAGE SQL;

内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理

标签：

相关文章推荐

新的分享

章节导航