To be found at

http://shark.armchair.mb.ca/~erwin

sira_prise wrote:

> To be found at
>
> http://shark.armchair.mb.ca/~erwin

What is this? It seems to be all about "relation variables" = "relvars"
such as

Name = JOBS
Predicate = $NM_JOB is a possible job.

Name = PRESIDENT
Predicate = The employee with employee number $NR_EMP has name
$NM_EMP, a monthly salary of $AM_SAL_MTHLY EUR, and
is the president of the company.

Name = DEPT
Predicate = Department $NR_DEPT is named $NM_DEPT, is located at
$NM_LOC, and is managed by employee $NR_EMP_MGR.

which seems like a terrible way to design a database, but perhaps an
interesting way to formally document the concepts represented by a
database.

That PRESIDENT example, in particular, is odd; it's only true for
one value of $NR_EMP (per company), whereas e.g. DEPT is true for
any value of $NR_DEPT (provided that the values of $NM_DEPT and
$NM_LOC and $NR_EMP_MGR are taken from the same row in the DB).