Обсуждение: Classes (Object Oriented) in PostgreSQL question

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Classes (Object Oriented) in PostgreSQL question

От
Nikola Milutinovic
Дата:
Hi all.

I'm in the process of redesigning my database. I have seen some space
for object design in my data schema. Namely, I'm modeling my company and
it has organizational units: "parts", "sectors", "divisions" and
"subdivisions". Each of these look alike and form a tree.

So I thought to create a table "org_unit" containing common fields and
just inferit them for a particular unit type. Something like:

CREATE TABLE org_unit (
   id        int4
    PRIMARY KEY,
   name        text,
   manager_id    int4,
   ordering    int2,
   print        boolean
);

CREATE TABLE ou_part (
) INFERITS (org_unit);

CREATE TABLE ou_sector (
   part_id    int4,
   FOREIGN KEY( part_id ) REFERENCES ou_part
) INHERITS (org_unit);
...
CREATE TABLE official_mail (
   id        int4    PRIMARY KEY,
   e_mail    text,
   org_unit_id    int4,
   FOREIGN KEY( org_unit_id ) REFERENCES org_unit
);

Will this work? Both the foreign key in ou_* and in official_mail?

Nix.

Re: Classes (Object Oriented) in PostgreSQL question

От
Stephan Szabo
Дата:
> Hi all.
>
> I'm in the process of redesigning my database. I have seen some space
> for object design in my data schema. Namely, I'm modeling my company and
> it has organizational units: "parts", "sectors", "divisions" and
> "subdivisions". Each of these look alike and form a tree.
>
> So I thought to create a table "org_unit" containing common fields and
> just inferit them for a particular unit type. Something like:
>
> CREATE TABLE org_unit (
>    id        int4
>     PRIMARY KEY,
>    name        text,
>    manager_id    int4,
>    ordering    int2,
>    print        boolean
> );
>
> CREATE TABLE ou_part (
> ) INFERITS (org_unit);
>
> CREATE TABLE ou_sector (
>    part_id    int4,
>    FOREIGN KEY( part_id ) REFERENCES ou_part
> ) INHERITS (org_unit);
> ...
> CREATE TABLE official_mail (
>    id        int4    PRIMARY KEY,
>    e_mail    text,
>    org_unit_id    int4,
>    FOREIGN KEY( org_unit_id ) REFERENCES org_unit
> );
>
> Will this work? Both the foreign key in ou_* and in official_mail?

Probably not how you want.  The references will currently
only reference the exact table you specify, not any of the
children.