Re: Need schema design advice
| От | Ben Chobot |
|---|---|
| Тема | Re: Need schema design advice |
| Дата | |
| Msg-id | 01074800-FA61-403A-A9D7-FD645A2E8958@silentmedia.com обсуждение исходный текст |
| Ответ на | Re: Need schema design advice (Martin Gainty <mgainty@hotmail.com>) |
| Ответы |
Re: Need schema design advice
|
| Список | pgsql-general |
On Oct 12, 2008, at 5:51 PM, Martin Gainty wrote:
could you provide a brief explanation of EAV ?
Instead of:
create table vehicles
(
kind text primary key,
wheels int
);
insert into vehicles (kind, wheels) values ('car',4);
insert into vehicles (kind, wheels) values ('bike',2);
create table boats
(
kind text primary key,
displacement int
);
insert into boats (kind,displacement) values ('small boat',1000);
insert into boats (kind,displacement) values ('big boat',300000);
... in an EAV model you would do something like:
create table eav
(
kind text primary key,
attr text,
value text
);
insert into eav (kind, attr, value) values ('car','wheels','4');
insert into eav (kind, attr, value) values ('bike','wheels','2');
insert into eav (kind, attr, value) values ('small boat','displacement','1000');
insert into eav (kind, attr, value) values ('big boat','displacement','300000');
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