On Sun, Sep 29, 2019 at 12:40 PM stan <st...@panix.com> wrote: > I have a table that consists of 3 columns. > > vendor_key > mfg_key > preferred (boolean) > > The idea is that a given vendor is the vendor we want to use for each > manufacturer for a given project. > > I need to constrain such that only on row of mfg, vendor and project can > be set to TRUE. > > Partial unique index
Example 3 on this page https://www.postgresql.org/docs/current/indexes-partial.html is exactly what you are looking for. John W Higgins > >
