[R] SQL implementations (was: Are you experienced in SAS and R ...)

[Douglas Bates]

Douglas Bates <bates at cs.wisc.edu> writes:

> My purpose is to give my opinions as a rather heave user of both MySQL
> and PostgreSQL.

That's a typo.  I meant to write "rather heavy user".

I was just creating a PostgreSQL database and realized another
advantage of PostgreSQL - in PostgreSQL tables you can use external
keys to enforce referential integrity.  In the example I was
describing where the records in the test score table include a student
identifier and a school identifier and a district identifier, I can
indicate in the definition of the table that the student id refers to
the primary key in the student table.  An attempt to insert a record
into the test score table with a student id that does not occur in the
student table will produce an error.
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