Stephane Bortzmeyer wrote: > If I define a primary key: > > name TEXT NOT NULL, > address INET, > PRIMARY KEY(name, address) > > the definition (seen by \d) becomes: > > name | text | not null > address | inet | not null > > "address" is now not null, which I do not want. It seems unnecessary: > I just want the tuple (name, address) to be unique, which seems > possible even if some 'address' values are NULL. > > It does not appear to be documented in > http://www.postgresql.org/docs/7.4/interactive/ddl-constraints.html#AEN1 975. > Is there a workaround? Per the SQL Commands Reference, under CREATE TABLE: "The primary key constraint specifies that a column or columns of a table may contain only unique (non-duplicate), nonnull values. Technically, PRIMARY KEY is merely a combination of UNIQUE and NOT NULL" Primary key columns cannot contain null values. -- Guy Rouillier ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to majordomo@xxxxxxxxxxxxxx
