Posted By: Anonymous
I have a table called
provider. I have three columns called
thing. There can be duplicate persons, duplicate places, and duplicate things, but there can never be a dupicate person-place-thing combination.
How would I ALTER TABLE to add a composite primary key for this table in MySQL with the these three columns?
ALTER TABLE provider ADD PRIMARY KEY(person,place,thing);
If a primary key already exists then you want to do this
ALTER TABLE provider DROP PRIMARY KEY, ADD PRIMARY KEY(person, place, thing);