Postgres日期重叠约束 [英] Postgres date overlapping constraint

问题描述

我有一个这样的表：

date_start    date_end     account_id    product_id
2001-01-01    2001-01-31   1             1
2001-02-01    2001-02-20   1             1
2001-04-01    2001-05-20   1             1

我要禁止给定（account_id，product_id）

编辑：我发现了一些东西：

I found something:

CREATE TABLE test (                                                                                                
    from_ts TIMESTAMPTZ,
    to_ts TIMESTAMPTZ,
    account_id INTEGER,
    product_id INTEGER,
    CHECK ( from_ts < to_ts ),
    CONSTRAINT overlapping_times EXCLUDE USING GIST (
        account_id WITH =,
        product_id WITH =,
        box(
            point( extract(epoch FROM from_ts at time zone 'UTC'), extract(epoch FROM from_ts at time zone 'UTC') ),
            point( extract(epoch FROM to_ts at time zone 'UTC') , extract(epoch FROM to_ts at time zone 'UTC') )
        ) WITH &&
    )
);

如果您想进一步了解> http://www.depesz.com/2010/01/03/waiting-for-8-5 -exclusion-constraints /

我唯一的问题是它不适用于空值作为结束时间戳，我想将其替换为无限值

My only problem is that it doesn't work with null values as a ending timestamp, I thought of replace it with infinite values but does not work as well.

推荐答案

好，我最终这样做了：

CREATE TABLE test (
    from_ts TIMESTAMPTZ,
    to_ts TIMESTAMPTZ,
    account_id INTEGER DEFAULT 1,
    product_id INTEGER DEFAULT 1,
    CHECK ( from_ts < to_ts ),
    CONSTRAINT overlapping_times EXCLUDE USING GIST (
        account_id WITH =,
        product_id WITH =,
        period(from_ts, CASE WHEN to_ts IS NULL THEN 'infinity' ELSE to_ts END) WITH &&
    )
);

与无穷大，交易证明完美配合。

Works perfectly with infinity, transaction proof.

我只需要安装时间扩展，该时间扩展将在postgres 9.2中原生，而btree_gist可在9.1中作为扩展使用。创建扩展btree_gist;

I just had to install temporal extension which is going to be native in postgres 9.2 and btree_gist available as an extension in 9.1 CREATE EXTENSION btree_gist;

nb：如果您没有null时间戳，则无需使用时间扩展，可以使用我的问题中指定的box方法。

nb : if you don't have null timestamp there is no need to use the temporal extension you could go with the box method as specified in my question.

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