Hi, Andreas,
Andreas Joseph Krogh wrote:
> create table onp_crm_businessfield_company(
> businessfield_id integer not null references onp_crm_businessfield(id),
> company_id integer not null references onp_crm_relation(id),
> is_preferred boolean,
> UNIQUE(businessfield_id, company_id)
> );
> I want a constraint on "is_preffered" so that it's only allowed to be set
> once
> pr. businessfield_id pr. company so that only one businessfield can be
> preferred for a company. Does anyone have an idea how to enforce this?
CREATE UNIQUE INDEX foo ON onp_crm_businessfield_company(company_id)
WHERE is_prefferred;
HTH,
Markus
--
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf. | Software Development GIS
Fight against software patents in EU! www.ffii.org www.nosoftwarepatents.org
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