| From: | "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com> |
|---|---|
| To: | Gregory Stark <stark(at)enterprisedb(dot)com> |
| Cc: | David Fetter <david(at)fetter(dot)org>, Edward Stanley <Edward(dot)Stanley(at)mcs(dot)vuw(dot)ac(dot)nz>, Richard Huxton <dev(at)archonet(dot)com>, Sean Utt <sean(at)strateja(dot)com>, Andrew Hammond <andrew(dot)george(dot)hammond(at)gmail(dot)com>, josh(at)agliodbs(dot)com, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: My honours project - databases using dynamically attached entity-properties |
| Date: | 2007-03-14 15:25:20 |
| Message-ID: | 45F813E0.6010503@commandprompt.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
Gregory Stark wrote:
> "David Fetter" <david(at)fetter(dot)org> writes:
>
>> CREATE TABLE symptom (
>> symptom_id SERIAL PRIMARY KEY, /* See above. */
>> ...
>> );
>>
>> CREATE TABLE patient_presents_with (
>> patient_id INTEGER NOT NULL REFERENCES patient(patient_id),
>> symptom_id INTEGER NOT NULL REFERENCES symptom(symptom_id),
>> UNIQUE(patient_id, symptom_id)
>> );
>
> I'm just glad I don't have your doctor. I hope mine doesn't think symptoms are
> all boolean values.
With a unique across (patient_id,symptom_id) you could have a single
patient with as many unique symptoms as could be listed.
Joshua D. Drake
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