Re: How to check for Overlapping Date Ranges with extra fields in table EXCLUDE constraint?

[Thomas Kellerer <shammat@xxxxxxx>]

Dionisis Kontominas schrieb am 26.07.2023 um 11:00:
> Hello all,
>
> In the Subject I mention what I am intending to do. Letme put some context; this is my table:
>
> portal_user_role
> (
>     f_id INTEGER NOT NULL,
>     f_portal_user_id INTEGER NOT NULL,
>     f_portal_role_id INTEGER NOT NULL,
>     f_is_active BOOLEAN NOT NULL,
>     f_is_deleted BOOLEAN NOT NULL,
>     f_start_date DATE NOT NULL,
>     f_end_date DATE,
>     f_created_on TIMESTAMP WITH TIME ZONE NOT NULL,
>     f_updated_on TIMESTAMP WITH TIME ZONE,
>     f_created_by CHARACTER VARYING(255) NOT NULL,
>     f_updated_by CHARACTER VARYING(255),
>     CONSTRAINT pk_portal_user_role PRIMARY KEY (f_id),
>     CONSTRAINT fk1_portal_user_role FOREIGN KEY (f_portal_user_id) REFERENCES portal_user (f_id),
>     CONSTRAINT fk2_portal_user_role FOREIGN KEY (f_portal_role_id) REFERENCES portal_role (f_id),
>     EXCLUDE USING gist (f_portal_user_id WITH =,
>                         f_portal_role_id WITH =,
>     DATERANGE(f_start_date, COALESCE(f_end_date, 'infinity'), '[]') WITH &&)
> );
>
> So, this table has a range of dates [f_start_date, f_end_date] that I
> do not want two records to overlap, for the same user, the same role
> and also when the f_is_deleted is TRUE only.
>
> I do not care for the records when the f_is_deleted is FALSE on them; i.e. they should not be part of the restriction/constraint. 
>
> How can I achieve this?

You can add a WHERE clause to the exclusion constraint (the condition must be enclosed in parentheses though):

    EXCLUDE USING gist (f_portal_user_id WITH =, f_portal_role_id WITH =, DATERANGE(f_start_date, f_end_date, '[]') WITH &&) where (f_is_deleted)

Note that you don't need COALESCE(f_end_date, 'infinity') because a daterange will treat null as infinity anyways.